diff --git "a/P2P_nucl-ex.json" "b/P2P_nucl-ex.json" new file mode 100644--- /dev/null +++ "b/P2P_nucl-ex.json" @@ -0,0 +1,4002 @@ +[ + { + "text": "Polarization transfer in the $^{16}$O$(p,p')$ reaction at forward angles\n and structure of the spin-dipole resonances: Cross sections and polarization transfer observables in the $^{16}$O$(p,p')$\nreactions at 392 MeV were measured at several angles between $\\theta_{lab}=$\n0$^\\circ$ and 14$^\\circ$. The non-spin-flip (${\\Delta}S=0$) and spin-flip\n(${\\Delta}S=1$) strengths in transitions to several discrete states and broad\nresonances in $^{16}$O were extracted using a model-independent method. The\ngiant resonances in the energy region of $E_x=19-$27 MeV were found to be\npredominantly excited by ${\\Delta}L=1$ transitions. The strength distribution\nof spin-dipole transitions with ${\\Delta}S=1$ and ${\\Delta}L=1$ were deduced.\nThe obtained distribution was compared with a recent shell model calculation.\nExperimental results are reasonably explained by distorted-wave impulse\napproximation calculations with the shell model wave functions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of inclusive charged-particle jet production in pp and p-Pb\n collisions at $\\sqrt{s_{\\rm NN}}=5.02$ TeV: Measurements of inclusive charged-particle jet production in pp and p-Pb\ncollisions at center-of-mass energy per nucleon-nucleon collision $\\sqrt{s_{\\rm\nNN}} = 5.02$ TeV and the corresponding nuclear modification factor $R_{\\rm\npPb}^{\\rm ch\\,jet}$ are presented, using data collected with the ALICE detector\nat the LHC. Jets are reconstructed in the central rapidity region $|\\eta_{\\rm\njet}| < 0.5$ from charged particles using the anti-$k_{\\rm T}$ algorithm with\nresolution parameters $R = 0.2$, 0.3, and 0.4. The $p_{\\rm T}$-differential\ninclusive production cross section of charged-particle jets, as well as the\ncorresponding cross-section ratios, are reported for pp and p-Pb collisions in\nthe transverse momentum range $10 < p^{\\rm ch}_{\\rm T,jet} < 140$ GeV/$c$ and\n$10 < p^{\\rm ch}_{\\rm T,jet} < 160$ GeV/$c$, respectively, together with the\nnuclear modification factor $R_{\\rm pPb}^{\\rm ch\\,jet}$ in the range $10 <\np^{\\rm ch}_{\\rm T,jet} < 140$ GeV/$c$. The analysis extends the $p_{\\rm T}$\nrange of the previously-reported charged-particle jet measurements by the ALICE\nCollaboration. The nuclear modification factor is found to be consistent with\none and independent of the jet resolution parameter with the improved precision\nof this study, indicating that the possible influence of cold nuclear matter\neffects on the production cross section of charged-particle jets in p-Pb\ncollisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV is smaller than the current\nprecision. The obtained results are in agreement with other minimum bias jet\nmeasurements available for RHIC and LHC energies, and are well reproduced by\nthe NLO perturbative QCD POWHEG calculations with parton shower provided by\nPYTHIA8 as well as by JETSCAPE simulations.", + "category": "nucl-ex" + }, + { + "text": "Fundamental Symmetries and Interactions: In Nuclear Physics numerous possibilities exist to investigate fundamental\nsymmetries and interactions. In particular, the precise measurements of\nproperties of fundamental fermions, searches for new interactions in\n$\\beta$-decays, and violations of discrete symmeties offer possibilities to\nsearch for physics beyond Standard Theory. Precise measurements of fundamental\nconstants can be carried out. Low energy experiments allow to probe New Physics\nat mass scales far beyond the reach of present accelerators or such planned for\nthe future and at which predicted new particles could be produced directly.", + "category": "nucl-ex" + }, + { + "text": "Measurement of charged jet cross section in pp collisions at\n ${\\sqrt{s}=5.02}$ TeV: The cross section of jets reconstructed from charged particles is measured in\nthe transverse momentum range of $5 Sigma^+ + K^+ + n at 3.5\nGeV beam energy. The extracted data allow to study in detail the invariant mass\ndistribution of the Sigma(1385)^+. The mass distribution is well described by a\nrelativistic Breit-Wigner function with a maximum at m_0 = 1383.2 +- 0.9\nMeV/c^2 and a width of 40.2 +- 2.1 MeV/c^2. The exclusive production\ncross-section comes out to be 22.27 +- 0.89 +- 1.56 +3.07 -2.10 mu b. Angular\ndistributions of the Sigma(1385)^+ in different reference frames are found to\nbe compatible with the hypothesis that 33 % of Sigma(1385)^+ result from the\ndecay of an intermediate Delta^{++} resonance.", + "category": "nucl-ex" + }, + { + "text": "Compton Scattering by the Proton using a Large-Acceptance Arrangement: Compton scattering by the proton has been measured using the tagged-photon\nfacility at MAMI (Mainz) and the large-acceptance arrangement LARA. The new\ndata are interpreted in terms of dispersion theory based on the SAID-SM99K\nparameterization of photo-meson amplitudes. It is found that two-pion exchange\nin the t-channel is needed for a description of the data in the second\nresonance region. The data are well represented if this channel is modeled by a\nsingle pole with mass parameter m(sigma)=600 MeV. The asymptotic part of the\nspin dependent amplitude is found to be well represented by pi-0-exchange in\nthe t-channel. A backward spin-polarizability of\ngamma(pi)=(-37.1+-0.6(stat+syst)+-3.0(model))x10^{-4}fm^4 has been determined\nfrom data of the first resonance region below 455 MeV. This value is in a good\nagreement with predictions of dispersion relations and chiral pertubation\ntheory. From a subset of data between 280 and 360 MeV the resonance\npion-photoproduction amplitudes were evaluated leading to a E2/M1 multipole\nratio of the p-to-Delta radiative transition of EMR(340\nMeV)=(-1.7+-0.4(stat+syst)+-0.2(model))%. It was found that this number is\ndependent on the parameterization of photo-meson amplitudes. With the MAID2K\nparameterization an E2/M1 multipole ratio of EMR(340\nMeV)=(-2.0+-0.4(stat+syst)+-0.2(model))% is obtained.", + "category": "nucl-ex" + }, + { + "text": "Trends in multiparticle production and some \"predictions\" for pp and\n PbPb collisions at LHC: Based on trends seen at lower energies we \"predict\" the multiplicities and\npseudorapidity distributions of particle density and elliptic flow that will be\nseen in PbPb and pp collisions at the LHC. We argue that, if these predictions\nturn out to be correct, either these quantities are insensitive to the state of\nmatter created in high energy heavy ion collisions or the observed simplicity\nand universality of the data must be telling us something profound about the\nmechanism of particle production, which to this date is not well understood.", + "category": "nucl-ex" + }, + { + "text": "Localized Charged-Neutral Fluctuations in 158 A GeV Pb+Pb Collisions: First results on the measurement of localized fluctuations in the\nmultiplicity of charged particles and photons produced in central 158 A GeV\nPb+Pb collisions are presented. The charged versus neutral correlations in\ncommon phase space regions of varying azimuthal size are analyzed by two\ndifferent methods. The measured results are compared to those from simulations\nand to those from different types of mixed events. The comparison indicates the\npresence of non-statistical fluctuations in both charged particle and photon\nmultiplicities in limited azimuthal regions. However, no correlated\ncharge-neutral fluctuations are observed.", + "category": "nucl-ex" + }, + { + "text": "Low Energy Threshold Analysis of the Phase I and Phase II Data Sets of\n the Sudbury Neutrino Observatory: Results are reported from a joint analysis of Phase I and Phase II data from\nthe Sudbury Neutrino Observatory. The effective electron kinetic energy\nthreshold used is T_eff=3.5 MeV, the lowest analysis threshold yet achieved\nwith water Cherenkov detector data. In units of 10^6 cm^{-2} s^{-1}, the total\nflux of active-flavor neutrinos from 8B decay in the Sun measured using the\nneutral current (NC) reaction of neutrinos on deuterons, with no constraint on\nthe 8B neutrino energy spectrum, is found to be Phi_NC = 5.140\n^{+0.160}_{-0.158} (stat) ^{+0.132}_{-0.117} (syst). These uncertainties are\nmore than a factor of two smaller than previously published results. Also\npresented are the spectra of recoil electrons from the charged current reaction\nof neutrinos on deuterons and the elastic scattering of electrons. A fit to the\nSNO data in which the free parameters directly describe the total 8B neutrino\nflux and the energy-dependent nu_e survival probability provides a measure of\nthe total 8B neutrino flux Phi_8B = 5.046 ^{+0.159}_{-0.152} (stat)\n^{+0.107}_{-0.123} (syst). Combining these new results with results of all\nother solar experiments and the KamLAND reactor experiment yields best-fit\nvalues of the mixing parameters of theta_{12}=34.06 ^{+1.16}_{-0.84} degrees\nand Delta m^2_{21}=7.59 ^{+0.20}_{-0.21} x 10^{-5} eV^2. The global value of\nPhi_8B is extracted to a precision of ^{+2.38}_{-2.95} %. In a three-flavor\nanalysis the best fit value of sin^2\\theta_{13} is 2.00 ^{+2.09}_{-1.63} x\n10^{-2}. Interpreting this as a limit implies an upper bound of\nsin^2\\theta_{13} < 0.057 (95% C. L.).", + "category": "nucl-ex" + }, + { + "text": "Evidence for $\\bar\u03bd_\u03bc\\to\\bar\u03bd_e$ Oscillations from the LSND\n Experiment at LAMPF: A search for $\\bar\\nu_{\\mu}\\to \\bar\\nu_{e}$ oscillations has been conducted\nat the Los Alamos Meson Physics Facility by using $\\bar\\nu_\\mu$ from $\\mu^+$\ndecay at rest. The $\\bar\\nu_e$ are detected via the reaction $\\bar\\nu_e\\,p\n\\rightarrow e^{+}\\,n$, correlated with a $\\gamma$ from $np\\rightarrow d\\gamma$\n($2.2\\,{\\rm MeV}$). The use of tight cuts to identify $e^+$ events with\ncorrelated $\\gamma$ rays yields 22 events with $e^+$ energy between 36 and\n$60\\,{\\rm MeV}$ and only $4.6 \\pm 0.6$ background events. A fit to the $e^+$\nevents between 20 and $60\\,{\\rm MeV}$ yields a total excess of\n$51.8^{+18.7}_{-16.9} \\pm 8.0$ events. If attributed to $\\bar \\nu_\\mu\n\\rightarrow \\bar \\nu_e$ oscillations, this corresponds to an oscillation\nprobability of ($0.31^{+0.11}_{-0.10} \\pm 0.05$)\\%.", + "category": "nucl-ex" + }, + { + "text": "Proton stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A GeV/c: The shape of proton rapidity distributions is analysed in terms of their\nGaussian components, and the average rapidity loss is determined in order to\nestimate the amount of stopping in C+C, d+C, C+Ta and d+Ta collisions at 4.2A\nGeV/c. Three Gaussians correspond to the nuclear transparency and describe well\nall peripheral and also C+C central collisions. Two-component shape is obtained\nin case of d+C and C+Ta central collisions. Finally one Gaussian, found in d+Ta\ncentral collisions, corresponds to the full stopping. The calculated values of\nthe average rapidity loss support the qualitative relationship between the\nnumber of Gaussian components and the corresponding stopping power. It is also\nobserved, in central collisions, that the average rapidity loss increases with\nthe ratio of the number of target and the number of projectile participants.", + "category": "nucl-ex" + }, + { + "text": "49Cr: Towards full spectroscopy up to 4 MeV: The nucleus 49Cr has been studied analysing gamma-gamma coincidences in the\nreaction 46Ti(alpha,n)49Cr at the bombarding energy of 12 MeV. The level scheme\nhas been greatly extended at low excitation energy and several new lifetimes\nhave been determined by means of the Doppler Shift Attenuation Method.\n Shell model calculations in the full pf configuration space reproduce well\nnegative-parity levels. Satisfactory agreement is obtained for positive parity\nlevels by extending the configuration space to include a nucleon-hole either in\nthe 1d3/2 or in the 2s1/2 orbitals.\n A nearly one-to-one correspondence is found between experimental and\ntheoretical levels up to an excitation energy of 4 MeV.\n Experimental data and shell model calculations are interpreted in terms of\nthe Nilsson diagram and the particle-rotor model, showing the strongly coupled\nnature of the bands in this prolate nucleus. Nine values of K(pi) are proposed\nfor the levels observed in this experiment.\n As a by-result it is shown that the values of the experimental magnetic\nmoments in 1f7/2 nuclei are well reproduced without quenching the nucleon\ng-factors.", + "category": "nucl-ex" + }, + { + "text": "Measurement of forward charged hadron flow harmonics in peripheral PbPb\n collisions at $\\sqrt{s_{NN}}=5.02$ TeV with the LHCb detector: Flow harmonic coefficients, $v_n$, which are the key to studying the\nhydrodynamics of the quark-gluon plasma (QGP) created in heavy-ion collisions,\nhave been measured in various collision systems, kinematic regions, and using\nvarious particle species. The study of flow harmonics in a wide pseudorapidity\nrange is particularly valuable to understand the temperature dependence of the\nshear viscosity to entropy density ratio of the QGP. This paper presents the\nfirst LHCb results of the second- and the third-order flow harmonic\ncoefficients of charged hadrons as a function of transverse momentum in the\nforward region, corresponding to pseudorapidities between 2.0 and 4.9, using\nthe data collected from PbPb collisions in 2018 at a center-of-mass energy of\n$5.02$ TeV. The coefficients measured using the two-particle angular\ncorrelation analysis method are smaller than the central-pseudorapidity\nmeasurements at ALICE and ATLAS from the same collision system but share\nsimilar features.", + "category": "nucl-ex" + }, + { + "text": "Search of parity violation effects in neutron reaction on natural Lead: Parity violation effects (PV) in nuclear reaction were discovered in the 60\nyears of the last century in the capture of thermal transversal polarized\nneutrons by 113Cd nucleus. In this reaction experimentally was measured a non\nzero asymmetry of emitted gamma quanta and the results was interpreted by the\nexistence of weak non leptonic interaction between nucleons in the compound\nnucleus. This first experimental result gave a serious impulse of theoretical\nand experimental developments of parity violation question in nuclear\nreactions. The weak interaction acts in the background of strong interaction\n(with order of magnitude higher) and therefore it is very difficult to observe\nand evidence it. One possibility is the evaluation of asymmetry effects induced\nby PV phenomena. For neutrons scattering there are a few asymmetry effects\n(like polarization of incident neutron beam, spin rotation and emitted neutrons\nasymmetry of incident transversal polarized neutrons) explained by the presence\nof weak interaction. In natural Lead were observed an unexpected high value of\nneutron spin rotation due to the PV phenomena. The natural Lead contains four\nisotopes and the main contribution to the PV effects is given by 204Pb. Further\nto explain the high value of neutron spin rotation it was supposed the\nexistence of a new negative P resonance with energy EP = - 16 eV. In this work\nwere estimated the PV effects in neutrons scattering in order to extract the\nweak matrix element and to verify the existence of the new negative resonance\nof 204Pb nucleus.", + "category": "nucl-ex" + }, + { + "text": "J/psi azimuthal anisotropy relative to the reaction plane in Pb-Pb\n collisions at 158 GeV per nucleon: The J/$\\psi$ azimuthal distribution relative to the reaction plane has been\nmeasured by the NA50 experiment in Pb-Pb collisions at 158 GeV/nucleon. Various\nphysical mechanisms related to charmonium dissociation in the medium created in\nthe heavy ion collision are expected to introduce an anisotropy in the\nazimuthal distribution of the observed J/$\\psi$ mesons at SPS energies. Hence,\nthe measurement of J/$\\psi$ elliptic anisotropy, quantified by the Fourier\ncoefficient v$_2$ of the J/$\\psi$ azimuthal distribution relative to the\nreaction plane, is an important tool to constrain theoretical models aimed at\nexplaining the anomalous J/$\\psi$ suppression observed in Pb-Pb collisions. We\npresent the measured J/$\\psi$ yields in different bins of azimuthal angle\nrelative to the reaction plane, as well as the resulting values of the Fourier\ncoefficient v$_{2}$ as a function of the collision centrality and of the\nJ/$\\psi$ transverse momentum. The reaction plane has been estimated from the\nazimuthal distribution of the neutral transverse energy detected in an\nelectromagnetic calorimeter. The analysis has been performed on a data sample\nof about 100 000 events, distributed in five centrality or p$_{\\rm T}$\nsub-samples. The extracted v$_{2}$ values are significantly larger than zero\nfor non-central collisions and are seen to increase with p$_{\\rm T}$.", + "category": "nucl-ex" + }, + { + "text": "Pseudorapidity dependence of long-range two-particle correlations in pPb\n collisions at sqrt(s[NN]) = 5.02 TeV: Two-particle correlations in pPb collisions at a nucleon-nucleon\ncenter-of-mass energy of 5.02 TeV are studied as a function of the\npseudorapidity separation (Delta eta) of the particle pair at small relative\nazimuthal angle (abs(Delta phi) < pi/3). The correlations are decomposed into a\njet component that dominates the short-range correlations (abs(Delta eta) < 1),\nand a component that persists at large Delta eta and may originate from\ncollective behavior of the produced system. The events are classified in terms\nof the multiplicity of the produced particles. Finite azimuthal anisotropies\nare observed in high-multiplicity events. The second and third Fourier\ncomponents of the particle-pair azimuthal correlations, V[2] and V[3], are\nextracted after subtraction of the jet component. The single-particle\nanisotropy parameters v[2] and v[3] are normalized by their lab frame\nmid-rapidity value and are studied as a function of eta[cm]. The normalized\nv[2] distribution is found to be asymmetric about eta[cm] = 0, with smaller\nvalues observed at forward pseudorapidity, corresponding to the direction of\nthe proton beam, while no significant pseudorapidity dependence is observed for\nthe normalized v[3] distribution within the statistical uncertainties.", + "category": "nucl-ex" + }, + { + "text": "Cross-sections and analyzing powers for $(p,n)$ reactions on ${}^{3}{\\rm\n He}$ and ${}^{4}{\\rm He}$ at 346 MeV: The cross-sections and analyzing powers for $(p,n)$ reactions on ${}^{3}{\\rm\nHe}$ and ${}^{4}{\\rm He}$ have been measured at a bombarding energy of $T_p$ =\n346 MeV and reaction angles of $\\theta_{\\rm lab}$ =\n$9.4^{\\circ}$--$27^{\\circ}$.\n The energy transfer spectra for ${}^{3}{\\rm He}(p,n)$ at large $\\theta_{\\rm\nlab}$ ($\\ge$ $16^{\\circ}$) are dominated by quasielastic contributions, and can\nbe reasonably reproduced by plane-wave impulse approximation (PWIA)\ncalculations for quasielastic scattering.\n By contrast, the known $L$ = 1 resonances in ${}^{4}{\\rm Li}$ are clearly\nobserved near the threshold in the ${}^{4}{\\rm He}(p,n)$ spectra.\n Because these contributions are remarkable at small angles, the energy\nspectra are significantly different from those expected for quasielastic\nscattering.\n The data are compared with the PWIA calculations, and it is found that the\nquasielastic contributions are dominant at large $\\theta_{\\rm lab}$ ($\\ge$\n$22^{\\circ}$).\n The nuclear correlation effects on the quasielastic peak for ${}^{4}{\\rm\nHe}(p,n)$ are also discussed.", + "category": "nucl-ex" + }, + { + "text": "Event-by-event mean p_T fluctuations in pp and Pb-Pb collisions measured\n by the ALICE experiment at the LHC: Non-statistical event-by-event fluctuations of the mean transverse momentum\nof charged particles in pp and Pb-Pb collisions are studied using the ALICE\nexperiment at the LHC. Little collision energy dependence is observed in pp.\nThe data indicate a common scaling behaviour with event multiplicity from pp to\nsemi-central Pb-Pb collisions. In central Pb-Pb, the results deviate from this\ntrend, exhibiting a significant reduction of the fluctuation strength. The\nresults are compared with measurements in Au-Au collisions at lower energies\nand with Monte Carlo simulations.", + "category": "nucl-ex" + }, + { + "text": "Beta-delayed neutron and gamma-ray spectroscopy of 17C utilizing\n spin-polarized 17B: Excited states in 17C were investigated through the measurement of\nbeta?-delayed neutrons and gamma rays emitted in the ? decay of 17B. In the\nmeasurement, three negative-parity states and two inconclusive states, were\nidentified in 17C above the neutron threshold energy, and seven gamma-lines\nwere identified in a beta?-delayed multiple neutron emission of the 17B ?\ndecay. From these transitions, the beta?-decay scheme of 17B was determined. In\nthe present work, the fibeta-NMR technique is combined with the ?-delayed\nparticle measurements using a fragmentation-induced spin-polarized 17B beam.\nThis new scheme allows us to determine the spin parity of beta?-decay feeding\nexcited states based on the difference in the discrete fibeta-decay asymmetry\nparameters, provided the states are connected through the Gamow-Teller\ntransition. In this work, 1/2-, 3/2-, and (5/2-) are assigned to the observed\nstates at Ex = 2.71(2), 3.93(2), and 4.05(2) MeV in 17C, respectively.", + "category": "nucl-ex" + }, + { + "text": "Single Particle Probes of d+Au Collisions in PHENIX: Deuteron-gold collisions provide insights into the nuclear structure function\nand a valuable baseline for Au+Au collisions. Measurement of the nuclear\nmodification factor, R_{dAu}, in d+Au in the PHENIX central arms for hadrons\nand photons allows us to disentangle cold nuclear matter effects from the hot\nmedium effects that are important in Au+Au collisions. In addition, the d+Au\nsystem can yield important insights into the gluonic structure of the Au\nnucleus. RHIC experiments have previously measured suppression of forward\nrapidity particle production relative to p+p scaled by the number of binary N-N\ncollisions, but a definitive explanation of these data is thus far elusive.\nCorrelations between hadrons with a large rapidity gap are a particularly\nsensitive probe of gluon saturation. We will discuss probing this physics via\nparticle production in events tagged with high momentum particles at different\nrapidities, along with R_{dAu} in new forward rapidity regions.", + "category": "nucl-ex" + }, + { + "text": "Evidence for top quark production in nucleus-nucleus collisions: Droplets of quark-gluon plasma (QGP), an exotic state of strongly interacting\nquantum chromodynamics (QCD) matter, are routinely produced in heavy nuclei\nhigh-energy collisions. Although the experimental signatures marked a paradigm\nshift away from expectations of a weakly coupled QGP, a challenge remains as to\nhow the locally deconfined state with a lifetime of a few fm can be resolved.\nThe only colored particle that decays mostly within the QGP is the top quark.\nHere we demonstrate, for the first time, that top quark decay products are\nidentified, irrespective of whether interacting with the medium (bottom quarks)\nor not (leptonically decaying W bosons). Using $1.7 \\pm 0.1\\,\\mathrm{nb^{-1}}$\nof lead-lead ($A = 208$) collision data recorded by the CMS experiment at a\nnucleon-nucleon center-of-mass energy of 5.02 TeV, we report evidence of top\nquark pair ($\\mathrm{t\\bar{t}}$) production. Dilepton final states are\nselected, and the cross section ($\\sigma_\\mathrm{t\\bar{t}}$) is measured from a\nlikelihood fit to a multivariate discriminator using lepton kinematic\nvariables. The $\\sigma_\\mathrm{t\\bar{t}}$ measurement is additionally performed\nconsidering the jets originating from the hadronization of bottom quarks, which\nimprove the sensitivity to the $\\mathrm{t\\bar{t}}$ signal process. After\nbackground subtraction and analysis corrections, the measured\n$\\sigma_\\mathrm{t\\bar{t}}$ is $2.02 \\pm 0.69\\,\\rm{(tot)}$ and $2.56\\pm\n0.82\\,\\rm{(tot)}\\,\\mu\\mathrm{b}$ in the two cases, respectively, consistent\nwith predictions from perturbative QCD.", + "category": "nucl-ex" + }, + { + "text": "Nuclear Modification Factor of $D^0$ Meson in Au+Au Collisions at\n $\\sqrt{s_{NN}}$ = 200 GeV: Heavy-flavor quarks are dominantly produced in initial hard scattering\nprocesses and experience the whole evolution of the system in heavy-ion\ncollisions at RHIC energies. Thus they are suggested to be an excellent probe\nto the medium properties through their interaction with the medium. In this\nproceedings, we report our first measurement of $D^0$ production via\ntopological reconstruction using STAR's recently installed Heavy Flavor Tracker\n(HFT). We also report our new measurement of Nuclear Modification Factor\n($R_{AA}$) of $D^0$ mesons in central Au+Au collisions at $\\sqrt{s_{NN}}$ = 200\nGeV as a function of transverse momentum ($p_{T}$). New results confirm the\nstrong suppression at high $p_{T}$ with a much improved precision, and show\nthat the $R_{AA}$ at high $p_{T}$ are comparable with light hadrons ($\\pi$) and\nwith D meson measurements at the LHC. Furthermore, several theoretical\ncalculations are compared to our data, and with charm diffusion coefficient\n2${\\pi}TD_{S}$ $\\sim$ 2-12 can reproduce both the $D^0$ $R_{AA}$ and $v_2$ data\nin Au+Au collisions at RHIC.", + "category": "nucl-ex" + }, + { + "text": "Charged particle distributions and nuclear modification at high\n rapidities in d+Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV: The measurements of the centrality dependence of $dN/d\\eta$ and transverse\nmomentum spectra from mid- to forward rapidity in d+Au collisions at\n$\\sqrt{s_{_{\\rm NN}}} =$ 200 GeV are reported. They provide a sensitive tool\nfor understanding the dynamics of multi-particle production in the high\nparton-density regime. In particular, we observe strong suppression of the\nnuclear modification factor $R_{CP}$ at forward rapidities (d-side, $\\eta$ =\n3.1) and enhancement at backward rapidity ($\\eta$ = $-$3.1). An empirical\nscaling is obtained for multiplicity and $R_{CP}$ when a shift of the\ncenter-of-mass in the asymmetric d+Au collisions with respect to the\nnucleon-nucleon system is applied.", + "category": "nucl-ex" + }, + { + "text": "Phenomenological description of neutron capture cross sections at 30 keV: Studying published data of Maxwellian averaged neutron capture cross\nsections, we found simple phenomenological rules obeyed by the cross sections\nas a function of proton and neutron number. We use these rules to make\npredictions for cross sections of neutron capture on nuclei with proton number\nabove 83, where very few data are available.", + "category": "nucl-ex" + }, + { + "text": "Comparison of the Total Charged-Particle Multiplicity in High-Energy\n Heavy Ion Collisions with e+e- and pp/pbar-p Data: The PHOBOS experiment at RHIC has measured the total multiplicity of primary\ncharged particles as a function of collision centrality in Au+Au collisions at\nsqrt(s_NN) = 19.6, 130 and 200 GeV. Above sqrt(s_NN) ~ 20 GeV, the total\nmultiplicity per participating nucleon pair (/) in central\nevents scales with sqrt(s) in the same way as in e+e- data. This is\nsuggestive of a universal mechanism of particle production in\nstrongly-interacting systems, controlled mainly by the amount of energy\navailable for particle production (per participant pair for heavy ion\ncollisions). The same effect has been observed in pp/pbar-p data after\ncorrecting for the energy taken away by leading particles. An approximate\nindependence of / on the number of participating nucleons is\nalso observed, reminiscent of ``wounded nucleon'' scaling ( proportional\nto ), but with the constant of proportionality set by the multiplicity\nmeasured in e+e- data rather than by pp/pbar-p data.", + "category": "nucl-ex" + }, + { + "text": "Development of a Gd Loaded Liquid Scintillator for Electron\n Anti-Neutrino Spectroscopy: We report on the development and deployment of 11.3 tons of 0.1% Gd loaded\nliquid scintillator used in the Palo Verde reactor neutrino oscillation\nexperiment. We discuss the chemical composition, properties, and stability of\nthe scintillator elaborating on the details of the scintillator preparation\ncrucial for obtaining a good scintillator quality and stability.", + "category": "nucl-ex" + }, + { + "text": "Resonance Production in Heavy-Ion Collisions: Hadronic resonances are unique probes that allow the properties of heavy-ion\ncollisions to be studied. Topics that can be studied include modification of\nspectral shapes, in-medium energy loss of parsons, vector-meson spin alignment,\nhydrodynamic flow, recombination, strangeness production, and the properties of\nthe hadronic phase. Measurements of resonances in p+p, p+A, and d+A collisions\nserve as baselines for heavy-ion studies and also permit searches for possible\ncollective effects in these smaller systems. These proceedings present a\nselection of results related to these topics from experiments at RHIC, LHC, and\nother facilities, as well as comparisons to theoretical models.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the nuclear modification factor of $b$-jets in 5.02 TeV\n Pb+Pb collisions with the ATLAS detector: This paper presents a measurement of $b$-jet production in Pb+Pb and $pp$\ncollisions at $\\sqrt{s_{_\\textrm{NN}}}=5.02$ TeV with the ATLAS detector at the\nLHC. The measurement uses 260 $\\textrm{pb}^{-1}$ of $pp$ collisions collected\nin 2017 and 1.4 $\\textrm{nb}^{-1}$ of Pb+Pb collisions collected in 2018. In\nboth collision systems, jets are reconstructed via the anti-$k_{t}$ algorithm.\nThe $b$-jets are identified from a sample of jets containing muons from the\nsemileptonic decay of $b$-quarks using template fits of the muon momentum\nrelative to the jet axis. In $pp$ collisions, $b$-jets are reconstructed for\nradius parameters $R= 0.2$ and $R= 0.4$, and only $R= 0.2$ jets are used in\nPb+Pb collisions. For comparison, inclusive $R= 0.2$ jets are also measured\nusing 1.7 $\\textrm{nb}^{-1}$ of Pb+Pb collisions collected in 2018 and the same\n$pp$ collision data as the $b$-jet measurement. The nuclear modification\nfactor, $R_\\textrm{AA}$, is calculated for both $b$-jets and inclusive jets\nwith $R= 0.2$ over the transverse momentum range of 80--290 GeV. The nuclear\nmodification factor for $b$-jets decreases from peripheral to central\ncollisions. The ratio of the $b$-jet $R_\\textrm{AA}$ to inclusive jet\n$R_\\textrm{AA}$ is also presented and suggests that the $R_\\textrm{AA}$ for\n$b$-jets is larger than that for inclusive jets in central Pb+Pb collisions.\nThe measurements are compared with theoretical calculations and suggest a role\nfor mass and colour-charge effects in partonic energy loss in heavy-ion\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "Sub- and above barrier fusion of loosely bound $^6$Li with $^{28}$Si: Fusion excitation functions are measured for the system $^6$Li+$^{28}$Si\nusing the characteristic $\\gamma$-ray method, encompassing both the sub-barrier\nand above barrier regions, viz., $E_{lab}$= 7-24 MeV. Two separate experiments\nwere performed, one for the above barrier region ($E_{lab}$= 11-24 MeV) and\nanother for the below barrier region ($E_{lab}$= 7-10 MeV). The results were\ncompared with our previously measured fusion cross section for the\n$^7$Li+$^{28}$Si system. We observed enhancement of fusion cross section at\nsub-barrier regions for both $^6$Li and $^7$Li, but yield was substantially\nlarger for $^6$Li. However, for well above barrier regions, similar type of\nsuppression was identified for both the systems.", + "category": "nucl-ex" + }, + { + "text": "Upsilon Measurements by the PHENIX Collaboration: PHENIX has measured $\\Upsilon$ production in p+p, d+Au and Au+Au collisions\nat $\\sqrt{s_{NN}}$=200 GeV. A baseline cross-section measurement has been made\nin p+p collisions. Preliminary studies of d+Au collisions found no suppression\nin the backward direction, but suppression was observed in the forward\ndirection indicating the presence of cold nuclear matter effects. In Au+Au\ncollisions preliminary studies of $\\Upsilon$ production at mid-rapidity found\nhints of suppression.", + "category": "nucl-ex" + }, + { + "text": "Observation of the 2$^+$ isomer in $^{52}$Co: We report the first observation of the 2$^+$ isomer in $^{52}$Co, produced in\nthe $\\beta$ decay of the 0$^+$, $^{52}$Ni ground state. We have observed three\n$\\gamma$-rays at 849, 1910, and 5185 keV characterizing the $\\beta$\nde-excitation of the isomer. We have measured a half-life of 102(6) ms for the\nisomeric state. The Fermi and Gamow-Teller transition strengths for the $\\beta$\ndecay of $^{52m}$Co to $^{52}$Fe have been determined. We also add new\ninformation on the $\\beta$ decay of the 6$^+$, $^{52}$Co ground state, for\nwhich we have measured a half-life of 112(3) ms.", + "category": "nucl-ex" + }, + { + "text": "Generalized Isoscaling of Isotopic Distributions: Generalized isoscaling relationships are proposed that may permit one to\nrelate the isotopic distributions of systems that may not be at the same\ntemperature. The proposed relationships are applied to multifragmentation\nexcitation functions for central Kr+Nb and Ar+Sc collisions.", + "category": "nucl-ex" + }, + { + "text": "Study of the $\u039bp$ Interaction Close to the $\u03a3^+n$ and\n $\u03a3^0p$ Thresholds: The $\\Lambda p$ interaction close to the $\\Sigma N$ threshold is considered.\nSpecifically, the pronounced structure seen in production reactions like $K^-d\n\\to \\pi^- \\Lambda p$ and $pp\\to K^+ \\Lambda p$ around the $\\Sigma N$ threshold\nis analyzed. Modern interaction models of the coupled $\\Lambda N - \\Sigma N$\nsystems generate such a structure either due to the presence of a\n(deuteron-like) unstable bound state or of an inelastic virtual state. % A\ndetermination of the position of the prominent peak as observed in various\nexperiments for the two aforementioned reactions leads to values that agree\nquite well with each other. Furthermore, the deduced mean value of $2128.7\\pm\n0.3$ MeV for the peak position coincides practically with the threshold energy\nof the $\\Sigma^+ n$ channel. This supports the interpretation of the structure\nas a genuine cusp, signaling an inelastic virtual state in the $^3S_1-^3D_1$\npartial wave of the $\\Sigma N$ isospin 1/2 channel. % There is also evidence\nfor a second peak (or shoulder) in the data sets considered which appears at\nroughly 10-15 MeV above the $\\Sigma N$ threshold. However, its concrete\nposition varies significantly from data set to data set and, thus, a\ntheoretical interpretation is difficult.", + "category": "nucl-ex" + }, + { + "text": "The Neutral Decay Modes of the Eta-Meson: The neutral decay modes of the eta meson are reviewed. The most recent\nresults obtained with the Crystal Ball multiphoton detector at BNL are\nincorporated. This includes a new, precise result for the slope parameter alpha\nof the Dalitz plot in eta -> 3pi0 decay and a new, lower branching ratio for\neta -> pi0 gamma gamma which is consistent with chiral perturbation theory.\nRecently-obtained limits are given for novel tests of CP and C invariance based\non several rare eta decays.", + "category": "nucl-ex" + }, + { + "text": "Electromagnetic Meson Production in the Nucleon Resonance Region: Recent experimental and theoretical advances in investigating electromagnetic\nmeson production reactions in the nucleon resonance region are reviewed.", + "category": "nucl-ex" + }, + { + "text": "Helicity-Dependent Angular Distributions for Double-Charged-Pion\n Photoproduction: Two-pion photoproduction in the reaction gamma p -> p pi+ pi- has been\nstudied at Jefferson Lab Hall B using a circularly-polarized tagged photon beam\nin the energy range between 0.6 GeV and 2.3 GeV. Beam-helicity-dependent\nangular distributions of the final-state particles were measured. The large\ncross-section asymmetries that have been found exhibit strong sensitivity to\nthe kinematics of the reaction, and are compared with preliminary model\ncalculations by Mokeev and Roberts.", + "category": "nucl-ex" + }, + { + "text": "The beta-gamma decay of 21Na: A new and independent determination of the Gamow-Teller branching ratio in\nthe beta-decay of 21Na is reported. The value obtained of 5.13 +- 0.43 % is in\nagreement with the currently adopted value and the most recent measurement. In\ncontrast to previous experiments, the present method was based on the counting\nof the parent 21Na ions and the resulting 351 keV gamma-rays without coincident\nbeta-particle detection.", + "category": "nucl-ex" + }, + { + "text": "Search for emission of unstable $^8$Be clusters from hot $^40$Ca and\n $^56$Ni nuclei: The possible occurence of highly deformed configurations is investigated in\nthe $^{40}$Ca and $^{56}$Ni di-nuclear systems as formed in the $^{28}$Si +\n$^{12}$C and $^{28}$Si + $^{28}$Si reactions, respectively, by using the\nproperties of emitted light charged particles. Inclusive as well as exclusive\ndata of the heavy fragments (A $\\geq$ 6) and their associated light charged\nparticles (p, d, t, and $\\alpha$-particles) have been collected at the IReS\nStrasbourg VIVITRON Tandem facility with two bombarding energies\n$E_{lab}(^{28}$Si) = 112 and 180 MeV by using the ICARE charged particle\nmultidetector array, which consists of nearly 40 telescopes. The measured\nenergy spectra, velocity distributions, in-plane and out-of-plane angular\ncorrelations are analysed by Monte Carlo CASCADE statistical-model calculations\nusing a consistent set of parameters with spin-dependent level densities.\nAlthough significant deformation effects at high spin are needed, the remaining\ndisagreement observed in the $^{28}$Si + $^{12}$C reaction for the S\nevaporation residue suggests an unexpected large unstable $^{8}$Be cluster\nemission of a binary nature.", + "category": "nucl-ex" + }, + { + "text": "Energy and rapidity dependence of electric charge correlations at\n 20-158GeV beam energies at the CERN SPS (NA49): Electric charge correlations are studied with the Balance Function method for\ncentral Pb + Pb collisions at the CERN - SPS. The results on centrality\nselected Pb + Pb interactions at 40 and 158 AGeV are presented for the first\ntime for two different rapidity intervals. In the mid-rapidity region a\ndecrease of the width with increasing centrality of the collision is observed\nwhereas in the forward rapidity region this effect vanishes. This could suggest\na delayed hadronization scenario. In addition, the results from a first attempt\nto study the energy dependence of the Balance Function throughout the whole SPS\nenergy range, are presented. The suitably scaled decrease of the width is\napproximately constant for the intermediate energies (30 to 80 AGeV) and gets\nstronger for the highest SPS and RHIC energies. On the other hand, both URQMD\nand HSD simulation results show no dependence on the collision energy.", + "category": "nucl-ex" + }, + { + "text": "Vertex Reconstruction Using a Single Layer Silicon Detector: Typical vertex finding algorithms use reconstructed tracks, registered in a\nmulti-layer detector, which directly point to the common point of origin. A\ndetector with a single layer of silicon sensors registers the passage of\nprimary particles only in one place. Nevertheless, the information available\nfrom these hits can also be used to estimate the vertex position, when the\ngeometrical properties of silicon sensors and the measured ionization energy\nlosses of the particles are fully exploited. In this paper the algorithm used\nfor this purpose in the PHOBOS experiment is described. The vertex\nreconstruction performance is studied using simulations and compared with\nresults obtained from real data. The very large acceptance of a single-layered\nmultiplicity detector permits vertex reconstruction for low multiplicity events\nwhere other methods, using small acceptance subdetectors, fail because of\ninsufficient number of registered primary tracks.", + "category": "nucl-ex" + }, + { + "text": "Energy dependence of inclusive photon elliptic flow in heavy-ion\n collision models: We present a comparison of inclusive photon elliptic flow parameter (v_{2})\nmeasured at RHIC and SPS high energy heavy-ion collision experiments to\ncalculations done using the AMPT and UrQMD models. The new results discussed\nincludes the comparison of the model calculations of photon v_{2} to\ncorresponding measurements at the forward rapidities. We observe that the AMPT\nmodel which includes partonic interactions and quark coalescence as a mechanism\nof hadronization is in good agreement with the measurements even at forward\nrapidities (2.3 < \\eta < 3.9) at RHIC as was previously observed for\nmeasurements at midrapidity. At the top SPS energy the contribution from\npartonic effects are smaller than that at RHIC energy, based on the comparison\nof the measured photon v_{2} with those from the AMPT default and UrQMD model\ncalculations. We find that if the measurements in RHIC beam energy scan (BES)\nand LHC energies would require an energy dependent partonic cross section in\nthe AMPT models, then the observed longitudinal scaling of v_{2} at top RHIC\nenergies (19.6-200 GeV) will be violated. We also discuss the relation between\nthe inclusive photon v_{2} and those of their parent \\pi^{0}'s for the beam\nenergies of 7.7 GeV to 2.76 TeV. The model results show that the transverse\nmomentum (p_{\\mathrm T}) integrated v_{2} of \\pi^{0} is larger by about 44%\nrelative to those of the inclusive photons. Finally we present the expectations\nof inclusive photon v_{2} for the RHIC beam energy scan (BES) program and LHC\nfrom the transport models, so that they can be compared to corresponding\nmeasurements using the data already collected at RHIC and LHC.", + "category": "nucl-ex" + }, + { + "text": "Evolution of structures in two particle correlations in RHIC Cu+Cu\n collisions as a function of centrality and momentum: Two particle correlation measurements in heavy ion collisions at RHIC have\nshown an extended near side correlation in $\\Delta\\eta$ relative to p+p for\nboth, momentum triggered and untriggered analyses. This phenomenon is also\nknown as the \"ridge\". An investigation into the momentum and centrality\ndependence of two particle correlations is presented for Cu+Cu 200 GeV\ncollisions from the STAR experiment. We extract the amplitude, $\\Delta\\eta$ and\n$\\Delta\\phi$ widths from the near side correlation structure, and show how its\nparameters depend on centrality and the lower transverse momentum cut-off.\nImplications for the origin of the ridge will be discussed.", + "category": "nucl-ex" + }, + { + "text": "Comment on 'Comparative study of beta-decay data for eight nuclides\n measured at the Physikalisch-Technische Bundesanstalt' [Astropart. Phys., 50,\n 47-58]: We would like to comment on a recent paper by Sturrock et al. [1] in which\nthe authors analyze decay data acquired by an ionization chamber in our\ninstitute. They interpret the variations in the data as solar-driven changes in\nthe decay rates of the radionuclides under study. In brief we would like to\ndiscuss and elucidate the properties and the origin of the data used by the\nauthors and explain why these data are not a sound basis for claiming evidence\nfor new physics.", + "category": "nucl-ex" + }, + { + "text": "Elliptic and hexadecapole flow of charged hadrons in Au+Au collisions at\n sqrt(s_NN) = 200 GeV: Differential measurements of the elliptic (v_2) and hexadecapole (v_4)\nFourier flow coefficients are reported for charged hadrons as a function of\ntransverse momentum (p_T) and collision centrality or the number of participant\nnucleons (N_part) for Au+Au collisions at sqrt(s_NN)=200 GeV. The v_{2,4}\nmeasurements at pseudorapidity |\\eta|<=0.35 obtained with four separate\nreaction plane detectors positioned in the range 1.0<|\\eta|<3.9 show good\nagreement, indicating the absence of significant \\eta-dependent nonflow\nperturbations. Sizable values for v_4(p_T) are observed with a ratio\nv_4(p_T,N_part)/v_2^2(p_T,N_part)~0.8 for 50200 this ratio increases up to 1.7 in the most central\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "Probable Level Densities and Radiative Strength Functions of Dipole\n gamma-Transitions in 57Fe Compound Nucleus: From the published results of experimental research of 56Fe(n,2gamma)\nreaction carried out in Budapest, the values of the most probable densities of\ncascade intermediate levels with 1/2, 3/2 spin and radiative strength functions\nof cascade E1 and M1 transitions in 57Fe compound nucleus have been determined.\nThese results correspond to analogous data for other nuclei studied by us and\ncontradict to predictions of conventional models.", + "category": "nucl-ex" + }, + { + "text": "Characterization of quasi-projectiles produced in symmetric collisions\n studied with INDRA Comparison with models: The characterization of hot quasi-projectiles produced in symmetric or\nquasi-symmetric reactions (Au + Au, Xe + Sn, Ni + Ni, Ar + KCl) at di erent\nincident energies are estimated by means of two di erent procedures. The\nadvantages and disadvantages of each method are analyzed on the basis of\nsimulations using events produced by two slightly di erent models: HIPSE and\nELIE.", + "category": "nucl-ex" + }, + { + "text": "Experimental and Simulation of Gamma Radiation Dose Rate for High\n Exposure Building Material: Natural radioactivity concentrations in high exposure building materials are\ncommonly used in Iran, which is measured a direct exposure by using\n{\\gamma}-ray spectrometry. The values for 226Ra, 232Th and 40K were in the\nranges 3.8 - 94.2, 6.5 - 172.2 and 556.9 - 1539.2 Bqkg-1, respectively. The\nabsorbed dose rates in the standard dwelling room due to 238U, 232Th series and\n40K were calculated with MCNPX code. The simulation and experimental results\nwere between 7.95 - 41.74 and 8.36 - 39.99 nGy h-1, respectively. These results\nwere compared with experimental outing and there was overlap closely. The\nsimulation results are able to develop for any kind of dwelling places.", + "category": "nucl-ex" + }, + { + "text": "Neutron form factor measurements at MAMI: Measurements of the electric and the magnetic neutron form factors have been\nperformed at the Mainz Microtron for more than 20 years. These MAMI experiments\nare reviewed in the context of measurements from other groups, and future\nmeasurements at MAMI are outlined.", + "category": "nucl-ex" + }, + { + "text": "Measurements of groomed-jet substructure of charm jets tagged by ${\\rm\n D}^0$ mesons in proton-proton collisions at $\\sqrt{s}$ = 13 TeV: Understanding the role of parton mass and Casimir colour factors in the\nquantum chromodynamics parton shower represents an important step in\ncharacterising the emission properties of heavy quarks. Recent experimental\nadvances in jet substructure techniques have provided the opportunity to\nisolate and characterise gluon emissions from heavy quarks. In this work, the\nfirst direct experimental constraint on the charm-quark splitting function is\npresented, obtained via the measurement of the groomed shared momentum fraction\nof the first splitting in charm jets, tagged by a reconstructed ${\\rm D}^0$\nmeson. The measurement is made in proton-proton collisions at $\\sqrt{s}$ = 13\nTeV, in the low jet transverse-momentum interval of $15 \\leq p_{\\rm T}^{\\rm\njet~ch} < 30$ GeV/$c$ where the emission properties are sensitive to parton\nmass effects. In addition, the opening angle of the first perturbative emission\nof the charm quark, as well as the number of perturbative emissions it\nundergoes, is reported. Comparisons to measurements of an inclusive-jet sample\nshow a steeper splitting function for charm quarks compared with gluons and\nlight quarks. Charm quarks also undergo fewer perturbative emissions in the\nparton shower, with a reduced probability of large-angle emissions.", + "category": "nucl-ex" + }, + { + "text": "Neutron lifetime measurements and effective spectral cleaning with an\n ultracold neutron trap using a vertical Halbach octupole permanent magnet\n array: Ultracold neutron (UCN) storage measurements were made in a trap constructed\nfrom a 1.3 T Halbach Octupole PErmanent (HOPE) magnet array aligned vertically,\nusing the TES-port of the PF2 source at the Institut Laue-Langevin. A\nmechanical UCN valve at the bottom of the trap was used for filling and\nemptying. This valve was covered with Fomblin grease to induce non-specular\nreflections and was used in combination with a movable polyethylene UCN remover\ninserted from the top for cleaning of above-threshold UCNs. Loss due to UCN\ndepolarization was suppressed with a minimum 2 mT bias field. Without using the\nUCN remover, a total storage time constant of $(712 \\pm 19)$ s was observed;\nwith the remover inserted for 80 s and used at either 80 cm or 65 cm from the\nbottom of the trap, time constants of $(824 \\pm 32)$ s and $(835 \\pm 36)$ s\nwere observed. Combining the latter two values, a neutron lifetime of\n$\\tau_{\\rm n} = (887 \\pm 39)$ s is extracted after primarily correcting for\nlosses at the UCN valve. The time constants of the UCN population during\ncleaning were observed and compared to calculations based on UCN kinetic theory\nas well as Monte-Carlo studies. These calculations are used to predict\nabove-threshold populations of $\\sim 5\\%$, $\\sim 0.5\\%$ and $\\sim 10^{-12}\\%$\nremaining after cleaning in the no remover, 80~cm remover and 65~cm remover\nmeasurements. Thus, by using a non-specular reflector covering the entire\nbottom of the trap and a remover at the top of the trap, we have established an\neffective cleaning procedure for removing a major systematic effect in\nhigh-precision $\\tau_{\\rm n}$ experiments with magnetically stored UCNs.", + "category": "nucl-ex" + }, + { + "text": "Improved limits on $\u03b2^+$EC and ECEC processes in $^{74}$Se: New limits on $\\beta^+$EC and ECEC processes in $^{74}$Se have been obtained\nusing a 600 cm$^3$ HPGe detector and an external source consisting of 1600 g of\na natural selenium powder. For different $\\beta^+$EC and ECEC transitions (to\nthe ground and excited states) obtained limits are on the level $\\sim\n(0.2-4.8)\\times10^{19}$ yr at 90\\% C.L. In particular, for the potentially\nresonant transition into the 1204.2 keV excited state of $^{74}$Ge a lower\nhalf-life limit of $1.1\\times10^{19}$ yr at 90\\% C.L. has been obtained.\nPossibility to increase the sensitivity of such measurements is discussed.", + "category": "nucl-ex" + }, + { + "text": "Electroweak Decay Studies of Highly Charged Radioactive Ions with TITAN\n at TRIUMF: Several modes of electroweak radioactive decay require an interaction between\nthe nucleus and bound electrons within the constituent atom. Thus, the\nprobabilities of the respective decays are not only influenced by the structure\nof the initial and final states in the nucleus, but can also depend strongly on\nthe atomic charge. Conditions suitable for the partial or complete ionization\nof these rare isotopes occur naturally in hot, dense astrophysical\nenvironments, but can also be artificially generated in the laboratory to\nselectively block certain radioactive decay modes. Direct experimental studies\non such scenarios are extremely difficult due to the laboratory conditions\nrequired to generate and store radioactive ions at high charge states. A new\nelectron-beam ion trap (EBIT) decay setup with the TITAN experiment at TRIUMF\nhas successfully demonstrated such techniques for performing spectroscopy on\nthe radioactive decay of highly charged ions.", + "category": "nucl-ex" + }, + { + "text": "Multiplicity and rapidity dependence of ${\\rm K}^*(892)^0$ and\n $\u03c6(1020)$ production in p-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV: The transverse-momentum ($p_{\\rm T}$) spectra of ${\\rm K}^*(892)^0$ and\n$\\phi(1020)$ measured with the ALICE detector up to $p_{\\rm T}$ = 16 GeV/$c$ in\nthe rapidity range $-1.2 < y < 0.3$, in p-Pb collisions at the center-of-mass\nenergy per nucleon-nucleon collision $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV are\npresented as a function of charged particle multiplicity and rapidity. The\nmeasured $p_{\\rm T}$ distributions show a dependence on both multiplicity and\nrapidity at low $p_{\\rm T}$ whereas no significant dependence is observed at\nhigh $p_{\\rm T}$. A rapidity dependence is observed in the $p_{\\rm\nT}$-integrated yield (d$N$/d$y$), whereas the mean transverse momentum ($\\left<\np_{\\rm T} \\right>$) shows a flat behavior as a function of rapidity. The\nrapidity asymmetry ($Y_{\\rm asym}$) at low $p_{\\rm T}$ ( < 5 GeV/$c$) is more\nsignificant for higher multiplicity classes. At high $p_{\\rm T}$, no\nsignificant rapidity asymmetry is observed in any of the multiplicity classes.\nBoth ${\\rm K}^*(892)^0$ and $\\phi(1020)$ show similar $Y_{\\rm asym}$. The\nnuclear modification factor ($Q_{\\rm CP}$) as a function of $p_{\\rm T}$ shows a\nCronin-like enhancement at intermediate $p_{\\rm T}$, which is more prominent at\nhigher rapidities (Pb-going direction) and in higher multiplicity classes. At\nhigh $p_{\\rm T}$ (> 5 GeV/$c$), the $Q_{\\rm CP}$ values are greater than unity\nand no significant rapidity dependence is observed.", + "category": "nucl-ex" + }, + { + "text": "Comment on \"Test of the Brink-Axel Hypothesis for the Pygmy Dipole\n Resonance\" [Phys. Rev. Lett. 119, 182503 (2017)]: The authors of the letter \"Test of the Brink-Axel Hypothesis for the Pygmy\nDipole Resonance\" [Phys. Rev. Lett. 119, 182503 (2017)] claim a violation of\nthe Brink-Axel hypothesis by (gamma,gamma') data from gELBE for 96Mo [Phys.\nRev. C 79, 061302 (2009)]. This violation cannot be concluded from the\n(gamma,gamma') data and is not at all discussed in that work. The comparison of\nthe (g,g') data with the new (p,p') data in the letter does not give any hint\nto such a violation.", + "category": "nucl-ex" + }, + { + "text": "Centrality dependence of electroweak boson production in PbPb collisions\n at the LHC: Recent data on the nuclear modification of W and Z boson production measured\nby the ATLAS collaboration in PbPb collisions at $\\sqrt{s_{\\rm nn}}=5.02$ TeV\nshow an enhancement in peripheral collisions, seemingly contradicting\npredictions of the Glauber model. The data were previously explained by arguing\nthat the nucleon-nucleon cross section may be shadowed in nucleus-nucleus\ncollisions, and hence suppressed compared to the proton-proton cross section at\nthe same collision energy. This interpretation has quite significant\nconsequences for the understanding of heavy-ion data, in particular in the\ncontext of the Glauber model. Instead, we provide an alternative explanation of\nthe data by assuming that there is a mild bias present in the centrality\ndetermination of the measurement; on the size of the related systematic\nuncertainty. Using this assumption, we show that the data is in agreement with\ntheoretical calculations using nuclear parton distribution functions. Finally,\nwe speculate that the centrality dependence of the W$^-$/W$^{+}$ ratio may\npoint to the relevance of a larger skin thickness of the Pb nucleus, which, if\npresent, would result in a few percent larger PbPb cross section than currently\naccounted for in the Glauber model and may hence be the root of the centrality\nbias.", + "category": "nucl-ex" + }, + { + "text": "Search for the critical point of strongly-interacting matter in\n ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c using scaled factorial\n moments of protons: The critical point of dense, strongly interacting matter is searched for at\nthe CERN SPS in ${}^{40}$Ar + ${}^{45}$Sc collisions at 150A GeV/c. The\ndependence of second-order scaled factorial moments of proton multiplicity\ndistribution on the number of subdivisions of transverse momentum space is\nmeasured. The intermittency analysis is performed using both transverse\nmomentum and cumulative transverse momentum. For the first time, statistically\nindependent data sets are used for each subdivision number. The obtained\nresults do not indicate any statistically significant intermittency pattern. An\nupper limit on the fraction of critical proton pairs and the power of the\ncorrelation function is obtained based on a comparison with the Power-law Model\ndeveloped for this purpose.", + "category": "nucl-ex" + }, + { + "text": "Study by the Methods of Physics of some Medieval Coins: A number of medieval coins from the Brukenthal Museum, Sibiu, Romania have\nbeen analyzed by the means of three methods: gamma transmission, X-ray\nfluoresecence and neutron activation analysis. The values of the concentrations\nof the elements determined given by the three methods are discussed.", + "category": "nucl-ex" + }, + { + "text": "Precision measurement of the quasi-free pn->dphi reaction close to\n threshold: The quasi-free pn->dphi reaction has been studied at the Cooler Synchrotron\nCOSY-Juelich, using the internal proton beam incident on a deuterium\ncluster-jet target and detecting a fast deuteron in coincidence with the K+K-\ndecay of the phi-meson. The energy dependence of the total and differential\ncross sections are extracted for excess energies up to 80 MeV by determining\nthe Fermi momentum of the target neutron on an event-by-event basis. Though\nthese cross sections are consistent with s-wave production, the kaon angular\ndistributions show the presence of p waves at quite low energy. Production on\nthe neutron is found to be stronger than on the proton but not by as much as\nfor the eta-meson.", + "category": "nucl-ex" + }, + { + "text": "Discovering the New Standard Model: Fundamental Symmetries and Neutrinos: This White Paper describes recent progress and future opportunities in the\narea of fundamental symmetries and neutrinos.", + "category": "nucl-ex" + }, + { + "text": "EXFOR-based simultaneous evaluation for fast neutron-induced fission\n cross section of thorium-232: The $^{232}$Th neutron-induced fission cross section was evaluated from 500\nkeV to 200 MeV. The experimental $^{232}$Th fission cross sections and their\nratios to the $^{235,238}$U fission cross sections in the EXFOR library were\nreviewed and analysed by the least-squares method. The newly published\n$^{232}$Th/$^{235}$U fission cross section ratios from the time-of-flight\nmeasurements at the CERN n_TOF and CSNS Back-n facilities were compiled in\nEXFOR. Additional simultaneous evaluation was performed by including the\nexperimental $^{233,238}$U and $^{239,240,241}$Pu fission cross sections and\ntheir ratios. The new evaluation provides the $^{232}$Th fission cross section\nsystematically lower than the JENDL-5 cross section. The reduction is 4% in the\nplateau region between 2 and 6 MeV and more significant in the subthreshold\nfission region. The present evaluation reduces the $^{232}$Th fission cross\nsection averaged over the $^{252}$Cf spontaneous fission neutron spectrum from\nthe JENDL-5 evaluation by 4%, which is closer to the other general purpose\nlibraries but underestimates Grundl et al's measurement by 11%.", + "category": "nucl-ex" + }, + { + "text": "Thermally-induced expansion in the 8 GeV/c $\u03c0^-$ + $^{197}$Au reaction: Fragment kinetic energy spectra for reactions induced by 8.0 GeV/c\n$\\rm{\\pi^-}$ beams incident on a $\\rm{^{197}}$Au target have been analyzed in\norder to deduce the possible existence and influence of thermal expansion. The\naverage fragment kinetic energies are observed to increase systematically with\nfragment charge but are nearly independent of excitation energy. Comparison of\nthe data with statistical multifragmentation models indicates the onset of\nextra collective thermal expansion near an excitation energy of E*/A\n$\\rm{\\approx}$ 5 MeV. However, this effect is weak relative to the radial\nexpansion observed in heavy-ion-induced reactions, consistent with the\ninterpretation that the latter expansion may be driven primarily by dynamical\neffects such as compression/decompression.", + "category": "nucl-ex" + }, + { + "text": "Symmetry energy from elliptic flow in 197Au + 197Au: The elliptic-flow ratio of neutrons with respect to protons or light complex\nparticles in reactions of neutron-rich systems at relativistic energies is\nproposed as an observable sensitive to the strength of the symmetry term in the\nequation of state at supra-normal densities. The results obtained from the\nexisting FOPI/LAND data for 197Au + 197Au collisions at 400 MeV/nucleon in\ncomparison with the UrQMD model favor a moderately soft symmetry term with a\ndensity dependence of the potential term proportional to rho/rho_0^gamma with\ngamma = 0.9 +- 0.4.", + "category": "nucl-ex" + }, + { + "text": "The CLAS Electromagnetic Calorimeter at Large Angles: The study of the response of the two modules of the large-angle\nelectromagnetic shower calorimeter (LAC) of the CLAS detector to charged and\nneutral particles is reported. The results agree very well with the Monte Carlo\nsimulation. The procedures adopted for the energy and timing calibration are\nalso discussed, proving that the module geometry allows for simple\nself-calibrating energy and timing algorithms.", + "category": "nucl-ex" + }, + { + "text": "Beta-decay properties of $^{25}$Si and $^{26}$P: The $\\beta$-decay properties of the neutron-deficient nuclei $^{25}$Si and\n$^{26}$P have been investigated at the GANIL/LISE3 facility by means of\ncharged-particle and $\\gamma$-ray spectroscopy. The decay schemes obtained and\nthe Gamow-Teller strength distributions are compared to shell-model\ncalculations based on the USD interaction. B(GT) values derived from the\nabsolute measurement of the $\\beta$-decay branching ratios give rise to a\nquenching factor of the Gamow-Teller strength of 0.6. A precise half-life of\n43.7 (6) ms was determined for $^{26}$P, the $\\beta$- (2)p decay mode of which\nis described.", + "category": "nucl-ex" + }, + { + "text": "Pionic Fusion of Heavy Ions: We report the first experimental observation of the pionic fusion of two\nheavy ions. The 12C(12C,24Mg)pi0 and 12C(12C,24Na)pi+ cross sections have been\nmeasured to be 208 +/- 38 and 182 +/- 84 picobarns, respectively, at E_cm = 137\nMeV. This cross section for heavy-ion pion production, at an energy just 6 MeV\nabove the absolute energy-conservation limit, constrains possible production\nmechanisms to incorporate the kinetic energy of the entire projectile-target\nsystem as well as the binding energy gained in fusion.", + "category": "nucl-ex" + }, + { + "text": "On the randomness and correlation in the trajectories of alpha particle\n emitted from ${}^{241}$Am: Statistical inference based on information entropy: Most particle detectors are based on the hypothesis that particles are\nemitted randomly upon nuclear decay. In the present work, we tested the\nhypothesis of the existence of correlation in the random trajectories of alpha\nparticles emitted from ${}^{241}$Am source and the null hypothesis of random\ntrajectories. The trajectories were clued through the registration of track in\na solid-state nuclear track detector. The experimental parameters were\noptimized to identify the possible sources of correlation in the track\nregistration and the detector conditions upon exposure and etching to avoid\nmisleading results. The optimization included authentication of linearity in\nregistration efficiency with exposure time to prevent coalescence of registered\ntracks. The statistical inference processes were based upon adaptive quadrates\nanalysis of the spatial data, and entropy and divergence analysis of the\nquadrate data together with the null hypothesis of Poisson distribution of\nrandom trajectories. The clustering and dispersion analysis were performed with\ncentral deviation tendency, empirical K-function, radial distribution analysis,\nand proximity Analysis. Results showed a pattern of gained information within\nthe registered tracks that may be attributed to the alteration in the alpha\nparticles' trajectories induced by the strong electric field due to atoms in\nthe source compound and encapsulation film.", + "category": "nucl-ex" + }, + { + "text": "Femtoscopy in heavy ion collisions: Wherefore, whence, and whither?: I present a brief overview of the wealth of femtoscopic measurements from the\npast two decades of heavy ion experiments. Essentially every conceivable knob\nat our disposal has been turned; the response of two-particle correlations to\nthese variations has revealed much about he space-momentum substructure of the\nhot source created in the collisions. I discuss the present status of the\nfemtoscopic program and questions which remain, and point to new efforts which\naim to resolve them.", + "category": "nucl-ex" + }, + { + "text": "Study of the production mechanism of the eta meson in proton-proton\n collisions by means of analysing power measurements: The analysing power measurements for the p(pol)p -> pp eta reaction studied\nin this dissertation are used in the determination of the reaction mechanism of\nthe eta meson production in nucleon-nucleon collisions.\n Measurements have been performed in the close-to-threshold energy region at\nbeam momenta of p(beam)=2.010 and 2.085 GeV/c, corresponding to the excess\nenergies of Q = 10 and 36 MeV, respectively. The experiments were realised by\nmeans of a cooler synchrotron and storage ring COSY along with a cluster jet\ntarget. For registration of the reaction products the COSY-11 facility has been\nused. The identification of the eta meson has been performed with the missing\nmass method.\n The results for the angular dependence of the analysing power combined with\nthe hitherto determined isospin dependence of the total cross section for the\n$\\eta$ meson production in the nucleon-nucleon collisions, reveal a\nstatistically significant indication that the excitation of the nucleon to the\nS_{11} resonance, the process which intermediates the production of the eta\nmeson, is predominantly due to the exchange of a pi meson between the colliding\nnucleons.\n The determined values of the analysing power at both excess energies are\nconsistent with zero implying that the eta meson is produced predominantly in\nthe s-wave at both excess energies.", + "category": "nucl-ex" + }, + { + "text": "Elliptic flow of charged particles in Pb-Pb collisions at 2.76 TeV: We report the first measurement of charged particle elliptic flow in Pb-Pb\ncollisions at 2.76 TeV with the ALICE detector at the CERN Large Hadron\nCollider. The measurement is performed in the central pseudorapidity region\n(|$\\eta$|<0.8) and transverse momentum range 0.2< $p_{\\rm T}$< 5.0 GeV/$c$. The\nelliptic flow signal v$_2$, measured using the 4-particle correlation method,\naveraged over transverse momentum and pseudorapidity is 0.087 $\\pm$ 0.002\n(stat) $\\pm$ 0.004 (syst) in the 40-50% centrality class. The differential\nelliptic flow v$_2(p_{\\rm T})$ reaches a maximum of 0.2 near $p_{\\rm T}$ = 3\nGeV/$c$. Compared to RHIC Au-Au collisions at 200 GeV, the elliptic flow\nincreases by about 30%. Some hydrodynamic model predictions which include\nviscous corrections are in agreement with the observed increase.", + "category": "nucl-ex" + }, + { + "text": "TRIGA-SPEC: A setup for mass spectrometry and laser spectroscopy at the\n research reactor TRIGA Mainz: The research reactor TRIGA Mainz is an ideal facility to provide neutron-rich\nnuclides with production rates sufficiently large for mass spectrometric and\nlaser spectroscopic studies. Within the TRIGA-SPEC project, a Penning trap as\nwell as a beam line for collinear laser spectroscopy are being installed.\nSeveral new developments will ensure high sensitivity of the trap setup\nenabling mass measurements even on a single ion. Besides neutron-rich fission\nproducts produced in the reactor, also heavy nuclides such as 235-U or 252-Cf\ncan be investigated for the first time with an off-line ion source. The data\nprovided by the mass measurements will be of interest for astrophysical\ncalculations on the rapid neutron-capture process as well as for tests of mass\nmodels in the heavy-mass region. The laser spectroscopic measurements will\nyield model-independent information on nuclear ground-state properties such as\nnuclear moments and charge radii of neutron-rich nuclei of refractory elements\nfar from stability. This publication describes the experimental setup as well\nas its present status.", + "category": "nucl-ex" + }, + { + "text": "Multi-particle azimuthal correlations for extracting event-by-event\n elliptic and triangular flow in Au$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$\n GeV: We present measurements of elliptic and triangular azimuthal anisotropy of\ncharged particles detected at forward rapidity $1<|\\eta|<3$ in Au$+$Au\ncollisions at $\\sqrt{s_{_{NN}}}=200$ GeV, as a function of centrality. The\nmultiparticle cumulant technique is used to obtain the elliptic flow\ncoefficients $v_2\\{2\\}$, $v_2\\{4\\}$, $v_2\\{6\\}$, and $v_2\\{8\\}$, and triangular\nflow coefficients $v_3\\{2\\}$ and $v_3\\{4\\}$. Using the small-variance limit, we\nestimate the mean and variance of the event-by-event $v_2$ distribution from\n$v_2\\{2\\}$ and $v_2\\{4\\}$. In a complementary analysis, we also use a folding\nprocedure to study the distributions of $v_2$ and $v_3$ directly, extracting\nboth the mean and variance. Implications for initial geometrical fluctuations\nand their translation into the final state momentum distributions are\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Correlation functions and emission time sequence of light charged\n particles from projectile-like fragment source in E/A = 44 and 77 MeV 40Ar +\n 27Al collisions: Two-particle correlation functions, involving protons, deuterons, tritons,\nand alpha-particles, have been measured at very forward angles (0.7 deg <\ntheta_lab < 7 deg), in order to study projectile-like fragment (PLF) emission\nin E/A = 44 and 77 MeV 40Ar + 27Al collisions. Peaks, originating from\nresonance decays, are larger at E/A = 44 than at 77 MeV. This reflects the\nlarger relative importance of independently emitted light particles, as\ncompared to two-particle decay from unstable fragments, at the higher beam\nenergy. The time sequence of the light charged particles, emitted from the PLF,\nhas been deduced from particle-velocity-gated correlation functions (discarding\nthe contribution from resonance decays). Alpha-particles are found to have an\naverage emission time shorter than protons but longer than tritons and\ndeuterons.", + "category": "nucl-ex" + }, + { + "text": "Measurement of neutron capture on $^{48}$Ca at thermal and thermonuclear\n energies: At the Karlsruhe pulsed 3.75\\,MV Van de Graaff accelerator the thermonuclear\n$^{48}$Ca(n,$\\gamma$)$^{49}$Ca(8.72\\,min) cross section was measured by the\nfast cyclic activation technique via the 3084.5\\,keV $\\gamma$-ray line of the\n$^{49}$Ca-decay. Samples of CaCO$_3$ enriched in $^{48}$Ca by 77.87\\,\\% were\nirradiated between two gold foils which served as capture standards. The\ncapture cross-section was measured at the neutron energies 25, 151, 176, and\n218\\,keV, respectively. Additionally, the thermal capture cross-section was\nmeasured at the reactor BR1 in Mol, Belgium, via the prompt and decay\n$\\gamma$-ray lines using the same target material. The\n$^{48}$Ca(n,$\\gamma$)$^{49}$Ca cross-section in the thermonuclear and thermal\nenergy range has been calculated using the direct-capture model combined with\nfolding potentials. The potential strengths are adjusted to the scattering\nlength and the binding energies of the final states in $^{49}$Ca. The small\ncoherent elastic cross section of $^{48}$Ca+n is explained through the nuclear\nRamsauer effect. Spectroscopic factors of $^{49}$Ca have been extracted from\nthe thermal capture cross-section with better accuracy than from a recent (d,p)\nexperiment. Within the uncertainties both results are in agreement. The\nnon-resonant thermal and thermonuclear experimental data for this reaction can\nbe reproduced using the direct-capture model. A possible interference with a\nresonant contribution is discussed. The neutron spectroscopic factors of\n$^{49}$Ca determined from shell-model calculations are compared with the values\nextracted from the experimental cross sections for $^{48}$Ca(d,p)$^{49}$Ca and\n$^{48}$Ca(n,$\\gamma$)$^{49}$Ca.", + "category": "nucl-ex" + }, + { + "text": "Experimental test of the time stability of the half-life of alpha-decay\n Po-214 nuclei: A method and results of an experimental test of the time stability of the\nhalf-life of alpha-decay Po-214 nuclei are presented. Two underground\ninstallations aimed at monitoring the time stability have been constructed.\nTime of measurement exceeds 1038 days for one set up and 562 days for the\nother. It was found that amplitude of possible annual variation of Po-214\nhalf-life does not exceed 0.2% of the mean value. The limit on the deviation of\nthe decay curve from exponent at 0.034\\times T_{1/2} pp eta' events the total width of the eta'\nmeson was determined to be 0.226 +- 0.017(stat.) +- 0.014(syst.) MeV/c^2.", + "category": "nucl-ex" + }, + { + "text": "Experimentally constrained $^{165,166}\\text{Ho}(n,\u03b3)$ rates and\n implications for the $s$ process: The $\\gamma$-ray strength function and the nuclear level density of\n$^{167}$Ho have been extracted using the Oslo method from a\n$^{164}\\text{Dy}(\\alpha,p\\gamma)^{167}$Ho experiment carried out at the Oslo\nCyclotron Laboratory. The level density displays a shape that is compatible\nwith %can be approximated with the constant temperature model in the\nquasicontinuum, while the strength function shows structures indicating the\npresence of both a scissors and a pygmy dipole resonance. Using our present\nresults as well as data from a previous\n$^{163}\\text{Dy}(\\alpha,p\\gamma)^{166}$Ho experiment, the\n$^{165}\\text{Ho}(n,\\gamma)$ and $^{166}\\text{Ho}(n,\\gamma)$ MACS uncertainties\nhave been constrained. The possible influence of the low-lying, long-lived\n6~keV isomer $^{166}$Ho in the $s$ process is investigated in the context of a\n2~$M_\\odot$, [Fe/H]=-0.5 AGB star. We show that the newly obtained\n$^{165}\\text{Ho}(n,\\gamma)$ MACS affects the final $^{165}$Ho abundance, while\nthe $^{166}\\text{Ho}(n,\\gamma)$ MACS only impacts the enrichment of\n$^{166,167}$Er to a limited degree due to the relatively rapid $\\beta$ decay of\nthe thermalized $^{166}$Ho at typical $s$-process temperatures.", + "category": "nucl-ex" + }, + { + "text": "Study of the partial wave structure of $\u03c0^0\u03b7$ photoproduction on\n protons: Analysis of the partial wave structure of gamma p --> pi0 eta p reaction is\npresented in the energy region from threshold up to the total center of mass\nenergy W = 1.9 GeV. Angular distributions measured with the Crystal Ball/TAPS\nhermetic detector system at the Mainz Microtron MAMI are expanded in terms of\nspherical harmonics. The relation of the extracted moments to the partial wave\nstructure of the reaction amplitude is discussed and compared with predictions\nfrom model calculations.", + "category": "nucl-ex" + }, + { + "text": "Multi-strange baryon production in pp collisions at $\\sqrt{s}$ = 7 TeV\n with ALICE: A measurement of the multi-strange $\\Xi^-$ and $\\Omega^-$ baryons and their\nantiparticles by the ALICE experiment at the CERN Large Hadron Collider (LHC)\nis presented for inelastic proton-proton collisions at centre of mass energy of\n7 TeV. The transverse momentum ($p_{\\rm T}$) distributions were studied at\nmid-rapidity (|y| < 0.5) in the range of 0.6 < $p_{\\rm T}$ < 8.5 GeV/$c$ for\n$\\Xi^-$ and $\\Xi^+$ baryons, and in the range of 0.8 < $p_{\\rm T}$ < 5 GeV/$c$\nfor $\\Omega^-$ and $\\Omega^+$. Baryons and antibaryons were measured as\nseparate particles and we find that the baryon to antibaryon ratio of both\nparticle species is consistent with unity over the entire range of the\nmeasurement. The statistical precision of the current LHC data has allowed us\nto measure a difference between the mean $p_{\\rm T}$ of $\\Xi^-$ ($\\Xi^+$) and\n$\\Omega^-$ ($\\Omega^+$). Particle yields, mean $p_{\\rm T}$, and the spectra in\nthe intermediate $p_{\\rm T}$ range are not well described by the PYTHIA Perugia\n2011 tune Monte Carlo event generator, which has been tuned to reproduce the\nearly LHC data. The discrepancy is largest for $\\Omega^-$ ($\\Omega^+$). This\nPYTHIA tune approaches the $p_{\\rm T}$ spectra of $\\Xi^-$ and $\\Xi^+$ baryons\nbelow $p_{\\rm T}$ < 0.85 GeV/$c$ and describes the $\\Xi^-$ and $\\Xi^+$ spectra\nabove $p_{\\rm T}$ > 6.0 GeV/$c$. We also illustrate the difference between the\nexperimental data and model by comparing the corresponding ratios of\n($\\Omega^{-}+\\Omega^+)/(\\Xi^-+\\Xi^+)$ as a function of transverse mass.", + "category": "nucl-ex" + }, + { + "text": "Production of Light (anti-)Nuclei with E864 at the AGS: Light nuclei can be produced in the central reaction zone via coalescence in\nrelativistic heavy ion collisions. E864 at BNL has measured the production of\nten stable light nuclei with nuclear number of A=1 to A=7 at rapidity\n$y\\simeq1.9$ and $p_{T}/A\\leq300MeV/c$. Data were taken with a Au beam of\nmomentum of 11.5 A $GeV/c$ on a Pb or Pt target with different experimental\nsettings. The invariant yields show a striking exponential dependence on\nnuclear number over ten orders of magnitudes with a penalty factor of about 50\nper additional nucleon. This penalty factor is used to estimate the strange\nquark matter (strangelet) production in the baryon rich and strangeness\nenhanced environment. The measurements of the production of antiproton,\nantideuteron, hypernuclei ($^{3}_{\\Lambda}H$,$^{4}_{\\Lambda}H$), and strongly\nunstable nuclear states ($^{4}H$,$^{5}Li$, $^{5}Li^{*}$, $^{5}He$) are\npresented as well. A model of local thermal equilibrium with radial flow at the\nkinetic freeze-out with a temperature of $T=112\\pm10MeV$, chemical potential of\n$\\mu_{B}=503\\pm20MeV$ and flow velocity of about\n$\\sqrt{V_{\\perp}^{2}}\\simeq0.5c$ seems to be able to describe the data in the\ngross scale with the exceptions of the production of antihyperons and\nhypernuclei. The large antihyperon production and the extra penalty for\nhypernuclei production are quite surprising.", + "category": "nucl-ex" + }, + { + "text": "Bose-Einstein correlations of direct photons in Au+Au collisions at\n $\\sqrt{s_{NN}} = 200$ GeV: The current status of the analysis of direct photon Bose-Einstein\ncorrelations in Au+Au collisions at $\\sqrt{s_{NN}}=200$ GeV done by the PHENIX\ncollaboration is summarized. All possible sources of distortion of the\ntwo-photon correlation function are discussed and methods to control them in\nthe PHENIX experiment are presented.", + "category": "nucl-ex" + }, + { + "text": "Thermal dileptons in high-energy nuclear collisions: Clear signs of excess dileptons above the known sources were found at the SPS\nsince long. However, a real clarification of these observations was only\nrecently achieved by NA60, measuring dimuons with unprecedented precision in\n158A GeV In-In collisions. The excess mass spectrum in the region M<1 GeV is\nconsistent with a dominant contribution from pi+pi- -> rho -> mu+mu-\nannihilation. The associated rho spectral function shows a strong broadening,\nbut essentially no shift in mass. In the region M>1 GeV, the excess is found to\nbe prompt, not due to enhanced charm production. The inverse slope parameter\nTeff associated with the transverse momentum spectra rises with mass up to the\nrho, followed by a sudden decline above. While the initial rise, coupled to a\nhierarchy in hadron freeze-out, points to radial flow of a hadronic decay\nsource, the decline above signals a transition to a low-flow source, presumably\nof partonic origin. The mass spectra show the steep rise towards low masses\ncharacteristic for Planck-like radiation. The polarization of the excess\nreferred to the Collins Soper frame is found to be isotropic. All observations\nare consistent with a global interpretation of the excess as thermal radiation.\nWe conclude with a short discussion of a possible link to direct photons.", + "category": "nucl-ex" + }, + { + "text": "Production of light flavour hadrons at intermediate and high pT in pp,\n p-Pb and Pb-Pb collisions measured with ALICE: Light flavour transverse momentum spectra at intermediate and high pT provide\nan important baseline for the measurement of perturbative QCD processes in pp,\nfor the evaluation of initial state effects in p-Pb, and for investigating the\nsuppression from parton energy loss in Pb-Pb collisions. The measurement of the\nnuclear modification factor RpPb for inclusive charged particles is extended up\nto 50 GeV/c in pT compared to our previous measurement and remains consistent\nwith unity up the largest momenta. Results on RpPb of charged pions, kaons and\nprotons that cover up to 14 GeV/c in pT are presented and compared to RpPb of\ninclusive charged particles. On the production of charged pions, kaons, and\nprotons up to pT = 20 GeV/c in Pb-Pb collisions final results for RAA are\npresented.", + "category": "nucl-ex" + }, + { + "text": "Hypernuclei - the next decade: We are at the verge of a new impact from hypernuclear experiments planned or\nalready operative at various laboratories all over the world. The complementary\nof these different experimental approaches to hypernuclei provides a wide basis\nfor a comprehensive understanding of strange hadrons in cold hadronic matter.\nHigh precision studies of light $\\Lambda$ hypernuclei, spectroscopy of double\n$\\Lambda\\Lambda$ nuclei and the properties of antihyperons in nuclei are\nexamples for the outstanding challenges for hypernuclei research in the next\ndecade.", + "category": "nucl-ex" + }, + { + "text": "Resonant Formation of $d\u03bct$ Molecules in Deuterium: An Atomic Beam\n Measurement of Muon Catalyzed dt Fusion: Resonant formation of $d\\mu t$ molecules in collisions of muonic tritium\n($\\mu t$) on D$_2$ was investigated using a beam of $\\mu t$ atoms,\ndemonstrating a new direct approach in muon catalyzed fusion studies. Strong\nepithermal resonances in $d\\mu t$ formation were directly revealed for the\nfirst time. From the time-of-flight analysis of $2036\\pm 116$ $dt$ fusion\nevents, a formation rate consistent with $0.73\\pm (0.16)_{meas} \\pm\n(0.09)_{model}$ times the theoretical prediction was obtained. For the largest\npeak at a resonance energy of $0.423 \\pm 0.037$ eV, this corresponds to a rate\nof $(7.1 \\pm 1.8) \\times 10^9$ s$^{-1}$, more than an order of magnitude larger\nthan those at low energies.", + "category": "nucl-ex" + }, + { + "text": "The Jefferson Lab 12 GeV Program: The Jefferson Lab facilities have undergone a substantial upgrade, both of\naccelerator, CEBAF, and of the experimental installations. We will discuss the\nprogress to completion of these facilities, the status of accelerator\ncommissioning, and the recent first operations for physics. We will then flesh\nout the anticipated exciting physics program of the next several years.", + "category": "nucl-ex" + }, + { + "text": "Measurements of azimuthal anisotropies in $^{16}$O+$^{16}$O and\n $\u03b3$+Au collisions from STAR: In this proceeding, we present the first measurements of azimuthal\nanisotropies, $v_2$ and $v_3$, in $^{16}$O+$^{16}$O collisions at 200 GeV as a\nfunction of transverse momentum and multiplicity, by using two- and\nfour-particle correlation methods. We compare our measurements with STAR\nmeasurements of $v_n$ in \\dau and \\heau collisions to provide insight into the\nimpact of system symmetry on initial condition for small systems. We also\ninvestigate the ratio $v_2\\{4\\}/v_2\\{2\\}$ as a function of centrality, which is\nexpected to be sensitive to nucleon-nucleon correlation in the $^{16}$O\nnucleus.", + "category": "nucl-ex" + }, + { + "text": "Dielectron production in proton-proton and proton-lead collisions at\n $\\sqrt{s_{\\rm{NN}}}$ = 5.02 TeV: The first measurements of dielectron production at midrapidity\n($|\\eta_{c}|<0.8$) in proton-proton and proton-lead collisions at\n$\\sqrt{s_{\\rm{NN}}}$ = 5.02 TeV at the LHC are presented. The dielectron cross\nsection is measured with the ALICE detector as a function of the invariant mass\n$m_{\\rm{ee}}$ and the pair transverse momentum $p_{\\rm{T,ee}}$ in the ranges\n$m_{\\rm{ee}}$ < 3.5 GeV/$c^{2}$ and $p_{\\rm{T,ee}}$ < 8.0 GeV/$c^{2}$, in both\ncollision systems. In proton-proton collisions, the charm and beauty cross\nsections are determined at midrapidity from a fit to the data with two\ndifferent event generators. This complements the existing dielectron\nmeasurements performed at $\\sqrt{s}$ = 7 and 13 TeV. The slope of the\n$\\sqrt{s}$ dependence of the three measurements is described by FONLL\ncalculations. The dielectron cross section measured in proton-lead collisions\nis in agreement, within the current precision, with the expected dielectron\nproduction without any nuclear matter effects for $\\rm{e}^{+}\\rm{e}^{-}$ pairs\nfrom open heavy-flavor hadron decays. For the first time at LHC energies, the\ndielectron production in proton-lead and proton-proton collisions are directly\ncompared at the same $\\sqrt{s_{\\rm{NN}}}$ via the dielectron nuclear\nmodification factor $R_{\\rm{pPb}}$. The measurements are compared to model\ncalculations including cold nuclear matter effects, or additional sources of\ndielectrons from thermal radiation.", + "category": "nucl-ex" + }, + { + "text": "Another look at anomalous J/Psi suppression in Pb+Pb collisions at P/A =\n 158 GeV/c: A new data presentation is proposed to consider anomalous $J/\\Psi$\nsuppression in Pb + Pb collisions at $P/A=158$ GeV/c. If the inclusive\ndifferential cross section with respect to a centrality variable is available,\none can plot the yield of J/Psi events per Pb-Pb collision as a function of an\nestimated squared impact parameter. Both quantities are raw experimental data\nand have a clear physical meaning. As compared to the usual J/Psi over\nDrell-Yan ratio, there is a huge gain in statistical accuracy. This\npresentation could be applied advantageously to many processes in the field of\nnucleus-nucleus collisions at various energies.", + "category": "nucl-ex" + }, + { + "text": "Intensities of the $\u03b3$-ray emissions following the $^{111}Sn$ decay\n determined via photonuclear reaction yield measurements: The intensities of the ten strongest $\\gamma$-ray transitions following the\n$^{111}Sn$ ($T_{1/2}$=35.3 m) decay have been determined via comparison of the\ntwo sets of the experimental photonucleon reaction yields driven using the\ntraditional activation equation and the activation equation for the genetically\ncoupled radioactive nuclei. The found absolute intensities of the $\\gamma$-ray\ntransitions in question were happened to be noticeably different from the\ncurrently recommended values.", + "category": "nucl-ex" + }, + { + "text": "Phenomenology of the $ppK^+K^-$ system near threshold: In this article studies of the near threshold $pp\\to ppK^+K^-$ reaction\nconducted with the COSY-11 and the ANKE detectors are reviewed. In particular\nrecent investigations on the $K^+K^-$ final state interaction are revisited\ntaking into account updated cross sections of the COSY-11 experiment. These\nstudies resulted in the new value of $K^+K^-$ effective range amounting to:\n$\\mathrm{Re}(b_{K^{+}K^{-}}) =\n-0.2^{+0.8_{stat}~+0.4_{sys}}_{-0.6_{stat}~-0.4_{sys}}~\\mathrm{fm}$ and\n$\\mathrm{Im}(b_{K^{+}K^{-}}) =\n1.2^{~+0.5_{stat}~+0.3_{sys}}_{~-0.3_{stat}~-0.3_{sys}}~\\mathrm{fm}$. The\ndetermined real and imaginary parts of the $K^+K^-$ scattering length were\nestimated to be: $\\left|\\mathrm{Re}(a_{K^{+}K^{-}})\\right| =\n10^{~+17_{stat}}_{~-10_{stat}}~\\mathrm{fm}$ and $\\mathrm{Im}(a_{K^{+}K^{-}}) =\n0^{~+37_{stat}}_{~-10_{stat}}~\\mathrm{fm}$.", + "category": "nucl-ex" + }, + { + "text": "\\textsc{MaGe} - a {\\sc Geant4}-based Monte Carlo Application Framework\n for Low-background Germanium Experiments: We describe a physics simulation software framework, MAGE, that is based on\nthe GEANT4 simulation toolkit. MAGE is used to simulate the response of\nultra-low radioactive background radiation detectors to ionizing radiation,\nspecifically the MAJORANA and GERDA neutrinoless double-beta decay experiments.\nMAJORANA and GERDA use high-purity germanium detectors to search for the\nneutrinoless double-beta decay of 76Ge, and MAGE is jointly developed between\nthese two collaborations. The MAGE framework contains the geometry models of\ncommon objects, prototypes, test stands, and the actual experiments. It also\nimplements customized event generators, GEANT4 physics lists, and output\nformats. All of these features are available as class libraries that are\ntypically compiled into a single executable. The user selects the particular\nexperimental setup implementation at run-time via macros. The combination of\nall these common classes into one framework reduces duplication of efforts,\neases comparison between simulated data and experiment, and simplifies the\naddition of new detectors to be simulated. This paper focuses on the software\nframework, custom event generators, and physics lists.", + "category": "nucl-ex" + }, + { + "text": "Determining $g_{A}/g_{V}$ with High Resolution Spectral Measurements\n Using an LiInSe$_2$ Bolometer: Neutrinoless Double-Beta decay (0$\\nu\\beta\\beta$) processes sample a wide\nrange of intermediate forbidden nuclear transitions, which may be impacted by\nquenching of the axial vector coupling constant ($g_A/g_V$), the uncertainty of\nwhich plays a pivotal role in determining the sensitivity reach of\n0$\\nu\\beta\\beta$ experiments. In this Letter, we present measurements performed\non a high-resolution LiInSe$_{2}$~ bolometer in a ''source=detector''\nconfiguration to measure the spectral shape of the 4-fold forbidden\n$\\beta$-decay of $^{115}$In. The value of $g_A/g_V$ is determined by comparing\nthe spectral shape of theoretical predictions to the experimental $\\beta$\nspectrum taking into account various simulated background components as well as\na variety of detector effects. We find evidence of quenching of $g_A/g_V$ at\n$>5\\sigma$ with a model-dependent quenching factor of $0.655\\pm0.002$ as\ncompared to the free-nucleon value for the Interacting Shell Model. We also\nmeasured the $^{115}$In half-life to be\n[$5.18\\pm0.06(\\text{stat.})^{+0.005}_{-0.015}(\\text{sys.})]\\times{10}^{14}$ yr\nwithin the Interacting Shell Model framework. This work demonstrates the power\nof the bolometeric technique to perform precision nuclear physics\nsingle-$\\beta$ decay measurements, which can help reduce the uncertainties in\nthe calculation of $0\\nu\\beta\\beta$ nuclear matrix elements.", + "category": "nucl-ex" + }, + { + "text": "Open heavy flavour production in ALICE: After a short review of the physics motivations for the study of open heavy\nflavour production in proton-proton, proton-nucleus and nucleus-nucleus\ncollisions at the LHC, we present results on the expected performance of the\nALICE experiment for charm and beauty production measurements.", + "category": "nucl-ex" + }, + { + "text": "Measurements of $\u03c0^\\pm$, $K^\\pm$, $p$ and $\\bar{p}$ spectra in\n $^{40}$Ar+$^{45}$Sc collisions at 13$A$ to 150$A$ GeV/$c$: The NA61/SHINE experiment at the CERN Super Proton Synchrotron studies the\nonset of deconfinement in strongly interacting matter through a beam energy\nscan of particle production in collisions of nuclei of varied sizes. This paper\npresents results on inclusive double-differential spectra, transverse momentum\nand rapidity distributions and mean multiplicities of $\\pi^\\pm$, $K^\\pm$, $p$\nand $\\bar{p}$ produced in $^{40}$Ar+$^{45}$Sc collisions at beam momenta of\n13$A$, 19$A$, 30$A$, 40$A$, 75$A$ and 150$A$~\\GeVc. The analysis uses the 10\\%\nmost central collisions, where the observed forward energy defines centrality.\nThe energy dependence of the $K^\\pm$/$\\pi^\\pm$ ratios as well as of inverse\nslope parameters of the $K^\\pm$ transverse mass distributions are placed in\nbetween those found in inelastic $p$+$p$ and central Pb+Pb collisions. The\nresults obtained here establish a system-size dependence of hadron production\nproperties that so far cannot be explained either within statistical or\ndynamical models.", + "category": "nucl-ex" + }, + { + "text": "J/$\u03c8$ production measurements by the PHENIX experiment at RHIC: Measurements of J/$\\psi$ production by the PHENIX experiment in p+p, d+Au,\nCu+Cu and Au+Au collisions at $\\sqrt{s_{NN}}$=200 GeV are reviewed. The results\nshow a suppression beyond what can be explained by cold nuclear matter effects\nin the most central Au+Au and to a lesser extent in Cu+Cu collisions. In\naddition, the suppression observed at mid rapidity in Au+Au is smaller than at\nforward rapidity, a tendency opposite to what is expected from the higher\nenergy density at mid rapidity. Regeneration, a possible explanation, can be\ntested by measuring the elliptic flow parameter v$_2$ of J/$\\psi$.", + "category": "nucl-ex" + }, + { + "text": "Direct photons in 200 GeV p+p, d+Au, and Au+Au from PHENIX: Direct photons were measured with the PHENIX experiment in p+p, d+Au, and\nAu+Au at sqrt(s_NN) = 200 GeV. To tackle the p_T region below 5 GeV/c, direct\nphotons were measured through their internal conversion into e^+e^- in Au+Au\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "The N = 16 spherical shell closure in 24O: The unbound excited states of the neutron drip-line isotope 24O have been\ninvestigated via the 24O(p,p')23O+n reaction in inverse kinematics at a beam\nenergy of 62 MeV/nucleon. The decay energy spectrum of 24O* was reconstructed\nfrom the momenta of 23O and the neutron. The spin-parity of the first excited\nstate, observed at Ex = 4.65 +/- 0.14 MeV, was determined to be Jpi = 2+ from\nthe angular distribution of the cross section. Higher lying states were also\nobserved. The quadrupole transition parameter beta2 of the 2+ state was\ndeduced, for the first time, to be 0.15 +/- 0.04. The relatively high\nexcitation energy and small beta2 value are indicative of the N = 16 shell\nclosure in 24O.", + "category": "nucl-ex" + }, + { + "text": "Characterization of a ballistic supermirror neutron guide: We describe the beam characteristics of the first ballistic supermirror\nneutron guide H113 that feeds the neutron user facility for particle physics\nPF1B of the Institute Laue-Langevin, Grenoble (ILL). At present, the neutron\ncapture flux density of H113 at its 20x6cm2 exit window is 1.35x10^10/cm^2/s,\nand will soon be raised to above 2x10^10/cm^2/s. Beam divergence is no larger\nthan beam divergence from a conventional Ni coated guide. A model is developed\nthat permits rapid calculation of beam profiles and absolute event rates from\nsuch a beam. We propose a procedure that permits inter-comparability of the\nmain features of beams emitted from ballistic or conventional neutron guides.", + "category": "nucl-ex" + }, + { + "text": "Are the Muonic Hydrogen and Electron Scattering Experiments Measuring\n the Same Observable?: Elastic scattering of relativistic electrons from the nucleon yields Lorentz\ninvariant form factors that describe the fundamental distribution of charge and\nmagnetism. The spatial dependence of the nucleon's charge and magnetism is\ntypically interpreted in the Breit reference frame which is related by a\nLorentz boost from the laboratory frame, where the nucleon is at rest. We\nconstruct a model to estimate how the Sachs electric and magnetic form factors\ncan be corrected for the effects of relativistic recoil. When the corrections\nare applied, the ratio of the proton's Sachs form factors is approximately flat\nwith $Q^2$, i.e. the spatial distributions of the proton's intrinsic charge and\nmagnetization are similar. Further, we estimate the correction due to recoil\nthat must be applied to the determination of the proton charge radius from\nelastic electron scattering before it can be compared to the value determined\nusing the Lamb shift in hydrogen. Application of the correction brings the two\nvalues of the proton charge radius into significantly closer agreement.\nPredicted corrections based on the model are provided for the rms charge radii\nof the deuteron, the triton, and the helium isotopes.", + "category": "nucl-ex" + }, + { + "text": "Prompt D$^{0}$, D$^{+}$, and D$^{*+}$ production in Pb-Pb collisions at\n $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV: The production of prompt D$^{0}$, D$^{+}$, and D$^{*+}$ mesons was measured\nat midrapidity (|y|< 0.5) in Pb-Pb collisions at the centre-of-mass energy per\nnucleon-nucleon pair $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV with the ALICE detector at\nthe LHC. The D mesons were reconstructed via their hadronic decay channels and\ntheir production yields were measured in central (0-10%) and semicentral\n(30-50%) collisions. The measurement was performed up to a transverse momentum\n($p_{\\rm T}$) of 36 or 50 GeV/$c$ depending on the D meson species and the\ncentrality interval. For the first time in Pb-Pb collisions at the LHC, the\nyield of D$^0$ mesons was measured down to $p_{\\rm T}$ = 0, which allowed a\nmodel-independent determination of the $p_{\\rm T}$-integrated yield per unit of\nrapidity (d$N$/d$y$). A maximum suppression by a factor 5 and 2.5 was observed\nwith the nuclear modification factor ($R_{\\rm AA}$) of prompt D mesons at\n$p_{\\rm T}$ = 6-8 GeV/$c$ for the 0-10% and 30-50% centrality classes,\nrespectively. The D-meson $R_{\\rm AA}$ is compared with that of charged pions,\ncharged hadrons, and J/$\\psi$ mesons as well as with theoretical predictions.\nThe analysis of the agreement between the measured $R_{\\rm AA}$, elliptic\n($v_2$) and triangular ($v_3$) flow, and the model predictions allowed us to\nconstrain the charm spatial diffusion coefficient $D_s$. Furthermore the\ncomparison of $R_{\\rm AA}$ and $v_2$ with different implementations of the same\nmodels provides an important insight into the role of radiative energy loss as\nwell as charm quark recombination in the hadronisation mechanisms.", + "category": "nucl-ex" + }, + { + "text": "Physics case for a polarised target for AFTER@LHC: We review a number of ideas put forward in favour of the use of a polarised\ntarget along with the proposed idea of a fixed-target experiment using the LHC\nbeams -- AFTER@LHC. A number of recent studies have shown that single\ntransverse-spin asymmetries (STSAs) are large enough to be precisely measured\nin the region accessible with AFTER@LHC, in particular as regards the Drell-Yan\nprocess as well as single-pion, isolated-photon and jet production. AFTER@LHC\nwith a polarised target would also be the ideal experimental set-up to measure\nthe gluon Sivers effect via a number of original quarkonium STSA studies. We\ndiscuss first figures-of-merit based on simulations for AFTER@LHC with a\npolarised target.", + "category": "nucl-ex" + }, + { + "text": "Spins and magnetic moments of 58;60;62;64Mn ground states and isomers: The odd-odd 54;56;58;60;62;64Mn isotopes (Z = 25) were studied using\nbunched-beam collinear laser spectroscopy at ISOLDE, CERN. From the measured\nhyperfine spectra the spins and magnetic moments of Mn isotopes up to N = 39\nwere extracted. The previous tentative ground state spin assignments of\n58;60;62;64Mn are now firmly determined to be I = 1 along with an I = 4\nassignment for the isomeric states in 58;60;62Mn. The I = 1 magnetic moments\nshow a decreasing trend with increasing neutron number while the I = 4 moments\nremain quite constant between N = 33 and N = 37. The results are compared to\nlarge-scale shell-model calculations using the GXPF1A and LNPS effective\ninteractions. The excellent agreement of the ground state moments with the\npredictions from the LNPS calculations illustrates the need for an increasing\namount of proton excitations across Z = 28 and neutron excitations across N =\n40 in the ground state wave functions from N = 37 onwards.", + "category": "nucl-ex" + }, + { + "text": "One-dimensional pion, kaon, and proton femtoscopy in Pb-Pb collisions at\n $\\sqrt{s_{\\rm {NN}}}$ =2.76 TeV: The size of the particle emission region in high-energy collisions can be\ndeduced using the femtoscopic correlations of particle pairs at low relative\nmomentum. Such correlations arise due to quantum statistics and Coulomb and\nstrong final state interactions. In this paper, results are presented from\nfemtoscopic analyses of $\\pi^{\\pm}\\pi^{\\pm}$, ${\\rm K}^{\\pm}{\\rm K}^{\\pm}$,\n${\\rm K}^{0}_S{\\rm K}^{0}_S$, ${\\rm pp}$, and ${\\rm \\overline{p}}{\\rm\n\\overline{p}}$ correlations from Pb-Pb collisions at $\\sqrt{s_{\\mathrm\n{NN}}}=2.76$ TeV by the ALICE experiment at the LHC. One-dimensional radii of\nthe system are extracted from correlation functions in terms of the invariant\nmomentum difference of the pair. The comparison of the measured radii with the\npredictions from a hydrokinetic model is discussed. The pion and kaon source\nradii display a monotonic decrease with increasing average pair transverse mass\n$m_{\\rm T}$ which is consistent with hydrodynamic model predictions for central\ncollisions. The kaon and proton source sizes can be reasonably described by\napproximate $m_{\\rm T}$-scaling.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the Beam-Normal Single-Spin Asymmetry for Elastic\n Electron Scattering from $^{12}$C and $^{27}$Al: We report measurements of the parity-conserving beam-normal single-spin\nelastic scattering asymmetries $B_n$ on $^{12}$C and $^{27}$Al, obtained with\nan electron beam polarized transverse to its momentum direction. These\nmeasurements add an additional kinematic point to a series of previous\nmeasurements of $B_n$ on $^{12}$C and provide a first measurement on $^{27}$Al.\nThe experiment utilized the Qweak apparatus at Jefferson Lab with a beam energy\nof 1.158 GeV. The average lab scattering angle for both targets was 7.7\ndegrees, and the average $Q^2$ for both targets was 0.02437 GeV$^2$ (Q=0.1561\nGeV). The asymmetries are $B_n$ = -10.68 $\\pm$ 0.90 stat) $\\pm$ 0.57 (syst) ppm\nfor $^{12}$C and $B_n$ = -12.16 $\\pm$ 0.58 (stat) $\\pm$ 0.62 (syst) ppm for\n$^{27}$Al. The results are consistent with theoretical predictions, and are\ncompared to existing data. When scaled by Z/A, the Q-dependence of all the\nfar-forward angle (theta < 10 degrees) data from $^{1}$H to $^{27}$Al can be\ndescribed by the same slope out to $Q \\approx 0.35$ GeV. Larger-angle data from\nother experiments in the same Q range are consistent with a slope about twice\nas steep.", + "category": "nucl-ex" + }, + { + "text": "Search for the Production of Element 112 in the 48Ca + 238U Reaction: We have searched for the production of element 112 in the reaction of 231 MeV\n48Ca with 238U. We have not observed any events with a \"one event\" upper limit\ncross section of 1.6 pb for EVR-fission events and 1.8 pb for EVR-alpha events.", + "category": "nucl-ex" + }, + { + "text": "Derivation and quantitative analysis of the differential\n self-interrogation Feynman-alpha method: A stochastic theory for a branching process in a neutron population with two\nenergy levels is used to assess the applicability of the differential\nself-interrogation Feynman-alpha method by numerically estimated reaction\nintensities from Monte Carlo simulations. More specifically, the variance to\nmean or Feynman-alpha formula is applied to investigate the appearing\nexponentials using the numerically obtained reaction intensities.", + "category": "nucl-ex" + }, + { + "text": "Forward Lambda Production and Nuclear Stopping Power in d + Au\n Collisions at sqrt(s_NN) = 200 GeV: We report the measurement of Lamda and Anti-Lamda yields and inverse slope\nparameters in d + Au collisions at sqrt(s_NN) = 200 GeV at forward and backward\nrapidities (y = +- 2.75), using data from the STAR forward time projection\nchambers. The contributions of different processes to baryon transport and\nparticle production are probed exploiting the inherent asymmetry of the d + Au\nsystem. Comparisons to model calculations show that the baryon transport on the\ndeuteron side is consistent with multiple collisions of the deuteron nucleons\nwith gold participants. On the gold side HIJING based models do not describe\nthe measured particle yields while models with initial state nuclear effects\nand/or hadronic rescattering do. The multichain model can provide a good\ndescription of the net baryon density in d + Au collisions at energies\navailable at the BNL Relativistic Heavy Ion Collider, and the derived\nparameters of the model agree with those from nuclear collisions at lower\nenergies.", + "category": "nucl-ex" + }, + { + "text": "Limiting temperatures and the Equation of State of Nuclear Matter: From experimental observations of limiting temperatures in heavy ion\ncollisions we derive Tc, the critical temperature of infinite nuclear matter.\nThe critical temperature is 16.6 +- 0.86 MeV. Theoretical model correlations\nbetween Tc, the compressibility modulus, K the effective mass, $m^*$ and the\nsaturation density, rho_s, are exploited to derive the quantity\n(K/m^*)**1/2*rho_s^{-1/3}$. This quantity together with calculations employing\nSkyrme and Gogny interactions indicates a nuclear matter incompressibility in\nmoderately excited nuclei that is in excellent agreement with the value\ndetermined from Giant Monopole Resonance data. This technique of extraction of\nK may prove particularly useful in investigations of very neutron rich systems\nusing radioactive beams.", + "category": "nucl-ex" + }, + { + "text": "Clustering in Nuclei from N/Z=1 to N/Z=2: The clustering of nucleons in nuclei is a widespread but elusive phenomenon\nfor study. Here, we wish to highlight the variety of theoretical approaches,\nand demonstrate how they are mutually supportive and complementary. On the\nexperimental side, we describe recent advances in the study of the classic\ncluster nucleus 24Mg. Also, recent studies of clustering in nuclei approaching\nthe neutron drip line are described. In the region near N/Z=2, both theory and\nexperiment now suggest that multi-centre cluster structure is important, in\nparticular for the very neutron rich beryllium isotopes.", + "category": "nucl-ex" + }, + { + "text": "Search for Deeply Bound Kaonic Nuclear States with AMADEUS: We briefly report on the search for Deeply Bound Kaonic Nuclear States with\nAMADEUS in the Sigma0 p channel following K- absorption on 12C and outline\nfuture perspectives for this work.", + "category": "nucl-ex" + }, + { + "text": "Systematics of azimuthal asymmetries in heavy ion collisions in the 1 A\n GeV regime: Using the large acceptance apparatus FOPI, we study central and semi-central\ncollisions in the reactions (energies in A GeV are given in parentheses):\n40Ca+40Ca (0.4, 0.6, 0.8, 1.0, 1.5, 1.93), 58Ni+58Ni (0.15, 0.25, 0.4),\n96Ru+96Ru (0.4, 1.0, 1.5), 96Zr+96Zr (0.4, 1.0, 1.5), 129Xe+CsI (0.15, 0.25,\n0.4), 197Au+197Au (0.09, 0.12, 0.15, 0.25, 0.4, 0.6, 0.8, 1.0, 1.2, 1.5). The\nobservables include directed and elliptic flow. The data are compared to\nearlier data where possible and to transport model simulations. A stiff nuclear\nequation of state is found to be incompatible with the data. Evidence for\nextra-repulsion of neutrons in compressed asymmetric matter is found.", + "category": "nucl-ex" + }, + { + "text": "NEUT Pion Final State Interactions: The pion final state interaction model in NEUT is described. Modifications\nand tuning of the model are validated against neutrino and non-neutrino (pion\nscattering and photoproduction) data. A method for evaluating the uncertainties\nin the model and propagation of systematic errors in a neutrino oscillation\nexperiment is described, using T2K as a specific example.", + "category": "nucl-ex" + }, + { + "text": "Strange Particle Production at RHIC: We report STAR measurements of mid-rapidity yields for the $\\Lambda$,\n$\\bar{\\Lambda}$, $K^{0}_{S}$, $\\Xi^{-}$, $\\bar{\\Xi}^{+}$, $\\Omega^{-}$, and\n$\\bar{\\Omega}^{+}$ particles in Cu+Cu and Au+Au $\\sqrt{s_{NN}} = 200$ GeV\ncollisions. We show that at a given number of participating nucleons, bulk\nstrangeness production is higher in Cu+Cu collisions compared to Au+Au\ncollisions at the same center of mass energy, counter to predictions from the\nCanonical formalism. We compare both the Cu+Cu and Au+Au yields to AMPT and\nEPOS predictions, and find they reproduce key qualitative aspects of the data.\nFinally, we investigate other scaling parameters and find bulk strangeness\nproduction for both the measured data and theoretical predictions, scales\nbetter with the number participants that undergo more than one collision.", + "category": "nucl-ex" + }, + { + "text": "Recent results on net-baryon fluctuations in ALICE: Recent results on the analysis of event-by-event net-baryon number\nfluctuations in Pb--Pb collisions at $\\sqrt{s_{\\mathrm{NN}}} = 2.76$ and $5.02$\nTeV are presented. The cumulants of the net-proton distributions, proxies for\nthe net-baryon distributions, up to third order are discussed. The experimental\nresults are compared with HIJING and EPOS model calculations and the dependence\nof fluctuation measurements on the phase-space coverage is addressed in the\ncontext of calculations from Lattice QCD (LQCD) and the Hadron Resonance Gas\n(HRG) model.", + "category": "nucl-ex" + }, + { + "text": "Saturation of azimuthal anisotropy in Au + Au collisions at sqrt(s_NN) =\n 62 - 200 GeV: New measurements are presented for charged hadron azimuthal correlations at\nmid-rapidity in Au+Au collisions at sqrt(s_NN) = 62.4 and 200 GeV. They are\ncompared to earlier measurements obtained at sqrt(s_NN) = 130 GeV and in Pb+Pb\ncollisions at sqrt(s_NN) = 17.2 GeV. Sizeable anisotropies are observed with\ncentrality and transverse momentum (p_T) dependence characteristic of elliptic\nflow (v_2). For a broad range of centralities, the observed magnitudes and\ntrends of the differential anisotropy, v_2(p_T), change very little over the\ncollision energy range sqrt(s_NN) = 62-200 GeV, indicating saturation of the\nexcitation function for v_2 at these energies. Such a saturation may be\nindicative of the dominance of a very soft equation of state for sqrt(s_NN) =\n62-200 GeV.", + "category": "nucl-ex" + }, + { + "text": "Upper Limit on the Chiral Magnetic Effect in Isobar Collisions at the\n Relativistic Heavy-Ion Collider: The chiral magnetic effect (CME) is a phenomenon that arises from the QCD\nanomaly in the presence of an external magnetic field. The experimental search\nfor its evidence has been one of the key goals of the physics program of the\nRelativistic Heavy-Ion Collider. The STAR collaboration has previously\npresented the results of a blind analysis of isobar collisions\n(${^{96}_{44}\\text{Ru}}+{^{96}_{44}\\text{Ru}}$,\n${^{96}_{40}\\text{Zr}}+{^{96}_{40}\\text{Zr}}$) in the search for the CME. The\nisobar ratio ($Y$) of CME-sensitive observable, charge separation scaled by\nelliptic anisotropy, is close to but systematically larger than the inverse\nmultiplicity ratio, the naive background baseline. This indicates the potential\nexistence of a CME signal and the presence of remaining nonflow background due\nto two- and three-particle correlations which are different between the\nisobars. In this post-blind analysis, we estimate the contributions from those\nnonflow correlations as a background baseline to $Y$, utilizing the isobar data\nas well as HIJING simulations. This baseline is found consistent with the\nisobar ratio measurement, and an upper limit of 10% at 95% confidence level is\nextracted for the CME fraction in the charge separation measurement in isobar\ncollisions at $\\sqrt{s_{\\rm NN}}=200$ GeV.", + "category": "nucl-ex" + }, + { + "text": "Density Dependence of the Symmetry energy and the Equation of State of\n Isospin Asymmetric Nuclear Matter: The density dependence of the symmetry energy in the equation of state of\nisospin asymmetric nuclear matter is studied using the isoscaling of the\nfragment yields and the antisymmetrized molecular dynamic calculation. It is\nobserved that the experimental data at low densities are consistent with the\nform of symmetry energy,E$_{sym}$ $\\approx$ 31.6 ($\\rho/\\rho_{\\circ})^{0.69}$,\nin close agreement with those predicted by the results of variational many-body\ncalculation. A comparison of the present result with those reported recently\nusing the NSCL-MSU data suggests that the heavy ion studies favor a dependence\nof the form, E$_{sym}$ $\\approx$ 31.6 ($\\rho/\\rho_{\\circ})^{\\gamma}$, where\n$\\gamma$ = 0.6 - 1.05. This constraints the form of the density dependence of\nthe symmetry energy at higher densities, ruling out an extremely \" stiff \" and\n\" soft \" dependences.", + "category": "nucl-ex" + }, + { + "text": "First Measurement of the Ar$(e,e^\\prime)X$ Cross Section at Jefferson\n Lab: The success of the ambitious programs of both long- and short-baseline\nneutrino-oscillation experiments employing liquid-argon time-projection\nchambers will greatly rely on the precision with which the weak response of the\nargon nucleus can be estimated. In the E12-14-012 experiment at Jefferson Lab\nHall A, we have studied the properties of the argon nucleus by scattering a\nhigh-quality electron beam off a high-pressure gaseous argon target. Here, we\npresent the measured $^{40}$Ar$(e,e^{\\prime})$ double differential cross\nsection at incident electron energy $E=2.222$~GeV and scattering angle $\\theta\n= 15.541^\\circ$. The data cover a broad range of energy transfers, where\nquasielastic scattering and delta production are the dominant reaction\nmechanisms. The result for argon is compared to our previously reported cross\nsections for titanium and carbon, obtained in the same kinematical setup.", + "category": "nucl-ex" + }, + { + "text": "Decomposing transverse momentum balance contributions for quenched jets\n in PbPb collisions at sqrt(s[NN]) = 2.76 TeV: Interactions between jets and the quark-gluon plasma produced in heavy ion\ncollisions are studied via the angular distributions of summed charged-particle\ntransverse momenta (pt) with respect to both the leading and subleading jet\naxes in high-pt dijet events. The contributions of charged particles in\ndifferent momentum ranges to the overall event pt balance are decomposed into\nshort-range jet peaks and a long-range azimuthal asymmetry in charged-particle\npt. The results for PbPb collisions are compared to those in pp collisions\nusing data collected in 2011 and 2013, at collision energy sqrt(s[NN]) = 2.76\nTeV with integrated luminosities of 166 inverse microbarns and 5.3 inverse\npicobarns, respectively, by the CMS experiment at the LHC. Measurements are\npresented as functions of PbPb collision centrality, charged-particle pt,\nrelative azimuth, and radial distance from the jet axis for balanced and\nunbalanced dijets.", + "category": "nucl-ex" + }, + { + "text": "Search for Spontaneous Radiation from Wavefunction Collapse in the\n Majorana Demonstrator: The Majorana Demonstrator neutrinoless double-beta decay experiment comprises\na 44 kg (30 kg enriched in $^{76}\\mathrm{Ge}$) array of $p$-type, point-contact\ngermanium detectors. With its unprecedented energy resolution and ultralow\nbackgrounds, Majorana also searches for rare event signatures from beyond\nstandard model physics in the low energy region below 100 keV. In this Letter,\nwe test the continuous spontaneous localization (CSL) model, one of the\nmathematically well-motivated wave function collapse models aimed at solving\nthe long-standing unresolved quantum mechanical measurement problem. While the\nCSL predicts the existence of a detectable radiation signature in the x-ray\ndomain, we find no evidence of such radiation in the 19--100 keV range in a\n37.5 kg-y enriched germanium exposure collected between December 31, 2015, and\nNovember 27, 2019, with the Demonstrator. We explored both the\nnon-mass-proportional (n-m-p) and the mass-proportional (m-p) versions of the\nCSL with two different assumptions: that only the quasifree electrons can emit\nthe x-ray radiation and that the nucleus can coherently emit an amplified\nradiation. In all cases, we set the most stringent upper limit to date for the\nwhite CSL model on the collapse rate, $\\lambda$, providing a factor of 40--100\nimprovement in sensitivity over comparable searches. Our limit is the most\nstringent for large parts of the allowed parameter space. If the result is\ninterpreted in terms of the Di\\`osi-Penrose gravitational wave function\ncollapse model, the lower bound with a 95% confidence level is almost an order\nof magnitude improvement over the previous best limit.", + "category": "nucl-ex" + }, + { + "text": "Competition of $\u03b2$-delayed protons and $\u03b2$-delayed $\u03b3$ rays\n in $^{56}$Zn and the exotic $\u03b2$-delayed $\u03b3$-proton decay: Remarkable results have been published recently on the $\\beta$ decay of\n$^{56}$Zn. In particular, the rare and exotic $\\beta$-delayed $\\gamma$-proton\nemission has been detected for the first time in the $fp$ shell. Here we focus\nthe discussion on this exotic decay mode and on the observed competition\nbetween $\\beta$-delayed protons and $\\beta$-delayed $\\gamma$ rays from the\nIsobaric Analogue State.", + "category": "nucl-ex" + }, + { + "text": "Jet reconstruction in heavy ion collisions (emphasis on Underlying Event\n background subtraction): A modification of the internal structure of jets is expected due to the\nproduction of a dense QCD medium, the Quark Gluon Plasma, in heavy-ion\ncollisions. We discuss some aspects of jet reconstruction in p+p and A+A\ncollisions and emphasize the dramatically increased contribution of the\nunderlying event in nucleus-nucleus collisions as compared with the vacuum\ncase. We conclude with its consequences on the full jet spectrum and\nfragmentation function extraction at LHC.", + "category": "nucl-ex" + }, + { + "text": "Elliptic flow of \u03c6-meson a sensitive probe for onset of\n de-confinement transition in high energy heavy-ion collisions: Elliptic flow (v_2) of \\phi-meson is shown to be a sensitive probe of the\npartonic collectivity using A Multi Phase Transport (AMPT) model. Within the\nambit of the AMPT model with partonic interactions (string melting version),\nthe \\phi-meson v_2 at midrapidity is found to have negligible contribution from\nhadronic interactions for Au+Au collisions at 200 GeV per nucleon. Changing the\nhadron cascade time in the model calculations does not change the \\phi-meson\nv_2, while it reduces the v_2 of proton at low transverse momentum (pT). These\nobservations indicate that a substantial reduction in \\phi-mesons v_2 as a\nfunction of colliding beam energy would suggest the dominance of hadronic\ninteractions over partonic interactions.", + "category": "nucl-ex" + }, + { + "text": "A Large Scale Double Beta and Dark Matter Experiment: GENIUS: The recent results from the HEIDELBERG-MOSCOW experiment have demonstrated\nthe large potential of double beta decay to search for new physics beyond the\nStandard Model. To increase by a major step the present sensitivity for double\nbeta decay and dark matter search much bigger source strengths and much lower\nbackgrounds are needed than used in experiments under operation at present or\nunder construction. We present here a study of a project proposed recently,\nwhich would operate one ton of 'naked' enriched GErmanium-detectors in liquid\nNItrogen as shielding in an Underground Setup (GENIUS). It improves the\nsensitivity to neutrino masses to 0.01 eV. A ten ton version would probe\nneutrino masses even down to 10^-3 eV. The first version would allow to test\nthe atmospheric neutrino problem, the second at least part of the solar\nneutrino problem. Both versions would allow in addition significant\ncontributions to testing several classes of GUT models. These are especially\ntests of R-parity breaking supersymmetry models, leptoquark masses and\nmechanism and right-handed W-boson masses comparable to LHC. The second issue\nof the experiment is the search for dark matter in the universe. The entire\nMSSM parameter space for prediction of neutralinos as dark matter particles\ncould be covered already in a first step of the full experiment - with the same\npurity requirements but using only 100 kg of 76Ge or even of natural Ge -\nmaking the experiment competitive to LHC in the search for supersymmetry.\n The layout of the proposed experiment is discussed and the shielding and\npurity requirements are studied using GEANT Monte Carlo simulations. As a\ndemonstration of the feasibility of the experiment first results of operating a\n'naked' Ge detector in liquid nitrogen are presented.", + "category": "nucl-ex" + }, + { + "text": "The elliptic flow of di-electrons in $\\sqrt{s_{NN}}$=200 GeV Au+Au\n collisions at STAR: In minimum bias (0-80%) Au+Au collisions at $\\sqrt{s_{NN}}$=200 GeV, the\nelliptic flow ($v_{2}$) measurements for di-electrons from the low to\nintermediate mass region are presented. The differential elliptic flow as a\nfunction of transverse momentum in different mass regions are also reported.\nThe simulated and measured $v_{2}$ of di-electrons are compared in the mass\nregions of $M_{ee}<0.14$ GeV/$c^{2}$ and $0.14 nn)/Gp(Lambda p -> np). The obtained\nratios for each hypernuclei support recent calculations based on short-range\ninteractions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of Angular Distributions of Drell-Yan Dimuons in $p + p$\n Interactions at 800 GeV/c: We report a measurement of the angular distributions of Drell-Yan dimuons\nproduced using an 800 GeV/c proton beam on a hydrogen target. The polar and\nazimuthal angular distribution parameters have been extracted over the\nkinematic range $4.5 < m_{\\mu \\mu} < 15$ GeV/c$^2$ (excluding the $\\Upsilon$\nresonance region), $0 < p_T < 4 $ GeV/c, and $0 < x_F < 0.8$. The $p+p$ angular\ndistributions are similar to those of $p+d$, and both data sets are compared\nwith models which attribute the $\\cos 2 \\phi$ distribution either to the\npresence of the transverse-momentum-dependent Boer-Mulders structure function\n$h_1^\\perp$ or to QCD effects. The data indicate the presence of both\nmechanisms. The validity of the Lam-Tung relation in $p+p$ Drell-Yan is also\ntested.", + "category": "nucl-ex" + }, + { + "text": "Non-photonic electron-hadron correlations in Cu+Cu at sqrt(s_NN) = 200\n GeV: In this paper we present the study of the azimuthal correlation function of\nnon-photonic electrons with low-pT hadrons produced in Cu+Cu collision at\nsqrt(s_NN)=200 GeV measured by STAR experiment at RHIC. Possible modification\nof the awayside peak is observed.", + "category": "nucl-ex" + }, + { + "text": "Worldwide Search for the Neutron EDM: Existing limits on the electric dipole moment (EDM) of the free neutron have\nprovided critical constraints on new sources of CP violation for more than 60\nyears. A new round of searches are actively underway with the goal of improving\nthe sensitivity to CP violation by up to two orders-of-magnitude. The status of\nthese new searches will be discussed, including recent progress on the nEDM\nexperiment to be carried out at the Fundamental Neutron Physics Beamline at the\nOak Ridge National Laboratory's Spallation Neutron Source.", + "category": "nucl-ex" + }, + { + "text": "Looking forward for Color Glass Condensate signatures: Forward $\\pi^0$ production has been measured at STAR with the new Forward\nMeson Spectrometer (FMS) from p+p and d+Au collisions during the 2008 RHIC run.\nWe present the first FMS results of azimuthal correlation involving a forward\n$\\pi^0$ produced in p+p and d+Au collisions to search for the onset of gluon\ndensity saturation, expected to occur at small momentum fractions.", + "category": "nucl-ex" + }, + { + "text": "Searching for Two-Neutrino and Neutrinoless Double Beta Decay of\n $^{134}$Xe with the PandaX-4T Experiment: $^{134}$Xe is a candidate isotope for neutrinoless double beta\ndecay~($0\\nu\\beta\\beta$) search. In addition, the two-neutrino case\n($2\\nu\\beta\\beta$) allowed by the Standard Model of particle physics has not\nyet been observed. Utilizing the 10.4% of $^{134}$Xe in the natural xenon in\nthe PandaX-4T detector and its first 94.9-day exposure, we have established the\nmost stringent constraints on $2\\nu\\beta\\beta$ and $0\\nu\\beta\\beta$ of\n$^{134}$Xe half-lives, with limits of $2.8\\times10^{22}$ yr and\n$3.0\\times10^{23}$ yr at 90% confidence level, respectively. The\n$2\\nu\\beta\\beta$ ($0\\nu\\beta\\beta$) limit surpasses the previously reported\nbest result by a factor of 32 (2.7), highlighting the potential of large\nmonolithic natural xenon detectors.", + "category": "nucl-ex" + }, + { + "text": "Complex fragment emission in low energy light-ion reactions: Inclusive energy spectra of the complex fragments (3 $\\leq$ Z $\\leq$ 5)\nemitted in the reactions $^{12}$C (77 MeV)+ $^{28}$Si, $^{11}$B (64 MeV)+\n$^{28}$Si and $^{12}$C (73 MeV)+ $^{27}$Al (all having the same excitation\nenergy of $ \\sim$ 67 MeV), have been measured in the angular range of\n10$^\\circ$ $\\lesssim \\theta_{lab} \\lesssim$ 60$^\\circ$. The fully energy damped\n(fusion-fission) and the partially energy damped (deep inelastic) components of\nthe fragment energy spectra have been extracted. It has been found that the\nyields of the fully energy damped fragments for all the above reactions are in\nconformity with the respective statistical model predictions. The time scales\nof various deep inelastic fragment emissions have been extracted from the\nangular distribution data. The angular momentum dissipation in deep inelastic\ncollisions has been estimated from the data and it has been found to be close\nto the corresponding sticking limit value.", + "category": "nucl-ex" + }, + { + "text": "Searches for transverse momentum dependent flow vector fluctuations in\n Pb-Pb and p-Pb collisions at the LHC: The measurement of azimuthal correlations of charged particles is presented\nfor Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}=$ 2.76 TeV and p-Pb collisions at\n$\\sqrt{s_{\\rm NN}}=$ 5.02 TeV with the ALICE detector at the CERN Large Hadron\nCollider. These correlations are measured for the second, third and fourth\norder flow vector in the pseudorapidity region $|\\eta|<0.8$ as a function of\ncentrality and transverse momentum $p_{\\rm T}$ using two observables, to search\nfor evidence of $p_{\\rm T}$-dependent flow vector fluctuations. For Pb-Pb\ncollisions at 2.76 TeV, the measurements indicate that $p_{\\rm T}$-dependent\nfluctuations are only present for the second order flow vector. Similar results\nhave been found for p-Pb collisions at 5.02 TeV. These measurements are\ncompared to hydrodynamic model calculations with event-by-event geometry\nfluctuations in the initial state to constrain the initial conditions and\ntransport properties of the matter created in Pb-Pb and p-Pb collisions.", + "category": "nucl-ex" + }, + { + "text": "Study of Proton Induced Reactions in a Radioactive 129-I Target at\n Ep=660 MeV: Two NaI (85% 129-I and 15% 127-I) targets were exposed to a beam of 660-MeV\nprotons. Cross sections for formation of 76 residual nuclei were obtained by\nthe induced activity method. The results are compared with other experimental\ndata on 127-I and theoretical calculations by eleven models contained in the\ncodes LAHET3 (using the Bertini+Dresner, ISABEL+Dresner, INCL+Dresner, and\nINCL+ABLA options), CASCADE, CEM95, CEM2K, LAQGSM+GEM2, CEM2k+GEM2,\nLAQGSM+GEMINI, and CEM2k+GEMINI. Most of the models describe spallation\nproducts with masses close to the target reasonably well while the reliability\nof the codes differs greatly in the deep spallation and fission/fragmentation\nregions. The difficulties in describing products with A=40-80 by all of the\ncodes tested here except for CEM2k+GEMINI and LAQGSM+GEMINI is related to the\nneglect of fission (and fragmentation) processes for targets as light as 129-I.", + "category": "nucl-ex" + }, + { + "text": "Search for the Hypothetical pi -> mu x Decay: The KARMEN collaboration has reported the possible observation of a hitherto\nunknown neutral and weakly interacting particle x, which is produced in the\ndecay pi -> mu + x with a mass m(x) = 33.9 MeV. We have searched for this\nhypothetical decay branch by studying muons from pion decay in flight with the\nLEPS spectrometer at the piE3 channel at PSI and find branching ratios BR(pi-\nto mu- anti-x) < 4e-7 and BR(pi+ to mu+ x) < 7e-8 (95\\% C.L.). Together with\nthe limit BR > 2e-8 derived in a recent theoretical paper our result would\nleave only a narrow region for the existence of x if it is a heavy neutrino.", + "category": "nucl-ex" + }, + { + "text": "Probing the statistical decay and alpha-clustering effects in 12c+12c\n and 14n+10b reactions: An experimental campaign has been undertaken at INFN Laboratori Nazionali di\nLegnaro, Italy, in order to progress in our understanding of the statistical\nproperties of light nuclei at excitation energies above particle emission\nthreshold, by measuring exclusive data from fusion-evaporation reactions. A\nfirst reaction 12C+12C at 7.9 AMeV beam energy has been measured, using the\nGARFIELD+Ring Counter experimental setup. Fusion-evaporation events have been\nexclusively selected. The comparison to a dedicated Hauser-Feshbach calculation\nallows us to give constraints on the nuclear level density at high excitation\nenergy for light systems ranging from C up to Mg. Out-of-equilibrium emission\nhas been evidenced and attributed both to entrance channel effects favoured by\nthe cluster nature of reaction partners and, in more dissipative events, to the\npersistence of cluster correlations well above the 24Mg threshold for 6 alphas\ndecay. The 24Mg compound nucleus has been studied with a new measurement 14N +\n10B at 5.7 AMeV. The comparison between the two datasets would allow us to\nfurther constrain the level density of light nuclei. Deviations from a\nstatistical behaviour can be analyzed to get information on nuclear clustering.", + "category": "nucl-ex" + }, + { + "text": "Liquid solution centrifugation for safe, scalable, and efficient isotope\n separation: A general method of separating isotopes by centrifuging dissolved chemical\ncompounds in a liquid solution is introduced. This technique can be applied to\nalmost all elements and leads to large separation factors. The method has been\ndemonstrated in several isotopic systems including Ca, Mo, O, and Li with\nsingle-stage selectivities of 1.046-1.067 per unit mass difference (e.g., 1.434\nin 40Ca/48Ca, 1.134 in 16O/18O), which are beyond the capabilities of various\nconventional methods of isotope enrichment. Equations are derived to model the\nprocess and the results agree with those of the experiments. The scalability of\nthe technique has been demonstrated by performing a three-stage enrichment of\n48Ca, and the scalability is more broadly supported through analogies to the\ngas centrifuge, whereby countercurrent centrifugation can further multiply the\nseparation factor by 5-10 times per stage in a continuous process. Optimal\ncentrifuge conditions and solutions can achieve both high-throughput and highly\nefficient isotope separation.", + "category": "nucl-ex" + }, + { + "text": "Precision Measurement of PArity Violation in Polarized Cold Neutron\n Capture on the Proton: the NPDGamma Experiment: The NPDGamma experiment at the Los Alamos Neutron Science Center (LANSCE) is\ndedicated to measure with high precision the parity violating asymmetry in the\n$\\gamma$ emission after capture of spin polarized cold neutrons in\npara-hydrogen. The measurement will determine unambiguously the weak\npion-nucleon-nucleon ($\\pi NN$) coupling constant {\\it f$^1_{\\pi}$}", + "category": "nucl-ex" + }, + { + "text": "First Measurement of the Ti$(e,e^\\prime){\\rm X}$ Cross Section at\n Jefferson Lab: To probe CP violation in the leptonic sector using GeV energy neutrino beams\nin current and future experiments using argon detectors, precise models of the\ncomplex underlying neutrino and antineutrino interactions are needed. The\nE12-14-012 experiment at Jefferson Lab Hall A was designed to perform a\ncombined analysis of inclusive and exclusive electron scatterings on both argon\n($N = 22$) and titanium ($Z = 22$) nuclei using GeV energy electron beams. The\nmeasurement on titanium nucleus provides essential information to understand\nthe neutrino scattering on argon, large contribution to which comes from\nscattering off neutrons. Here we report the first experimental study of\nelectron-titanium scattering as double differential cross section at beam\nenergy $E=2.222$ GeV and electron scattering angle $\\theta = 15.541$ deg,\nmeasured over a broad range of energy transfer, spanning the kinematical\nregions in which quasielastic scattering and delta production are the dominant\nreaction mechanisms. The data provide valuable new information needed to\ndevelop accurate theoretical models of the electromagnetic and weak cross\nsections of these complex nuclei in the kinematic regime of interest to\nneutrino experiments.", + "category": "nucl-ex" + }, + { + "text": "Test of Time Reversal Invariance in Polarized Proton-Deuteron Scattering: A novel test of time-reversal invariance in proton-deuteron scattering is\nplanned as an internal target transmission experiment at the cooler synchrotron\nCOSY. The P-even, T-odd observable is the polarization correlation $A_{y,xz}$\nof the total cross section measured using a polarized internal proton beam\n(polarization $p_y$) and an internal polarized deuterium target (tensor\npolarization $p_{xz}$). Measuring this observable is a true null test of time\nreversal invariance and therefore allows to reach a high accuracy. Sufficient\nluminosity can be obtained using a window-less storage cell placed on the axis\nof the proton beam. Tensor polarized atoms are produced in an atomic beam\nsource based on Stern-Gerlach separation in permanent sextupole magnets and\nadiabatic high frequency transitions. The total cross section correlation is\nmeasured by monitoring the beam transmission in the COSY storage ring mode of\noperation. The proton beam momentum will be in the range 2-3 GeV/c. This\nmomentum is ideally suited to test possible short range contributions, i.e.\nnatural parity charged $\\rho$-type and unnatural parity $a_1$-type meson\nexchange contributions. The feasibility of the experiment, systematic errors\nand the expected accuracy are discussed.", + "category": "nucl-ex" + }, + { + "text": "Precision study of the d+p->3He+eta reaction for excess energies between\n 20 and 60 MeV: The differential and total cross sections for the d+p->3He+eta reaction have\nbeen measured at COSY-ANKE at excess energies of 19.5, 39.4, and 59.4 MeV over\nthe full angular range. The results are in line with trends apparent from the\ndetailed near-threshold studies and also agree with those from CELSIUS, though\nthe present data have higher precision. While at 19.5 MeV the results can be\ndescribed in terms of s- and p-wave production, by 59.4 MeV higher partial\nwaves are required. Including the 19.5 MeV point together with the\nnear-threshold data in a global s- and p-wave fit gives a poorer overall\ndescription of the data though the position of the pole in the 3He scattering\namplitude, corresponding to the quasi-bound or virtual state, is hardly\nchanged.", + "category": "nucl-ex" + }, + { + "text": "Constraints on the Nucleon Strange Form Factors at Q^2 ~ 0.1 GeV^2: We report the most precise measurement to date of a parity-violating\nasymmetry in elastic electron-proton scattering. The measurement was carried\nout with a beam energy of 3.03 GeV and a scattering angle =6\ndegrees, with the result A_PV = -1.14 +/- 0.24 (stat) +/- 0.06 (syst) parts per\nmillion. From this we extract, at Q^2 = 0.099 GeV^2, the strange form factor\ncombination G_E^s + 0.080 G_M^s = 0.030 +/- 0.025 (stat) +/- 0.006 (syst) +/-\n0.012 (FF) where the first two errors are experimental and the last error is\ndue to the uncertainty in the neutron electromagnetic form factor. This result\nsignificantly improves current knowledge of G_E^s and G_M^s at Q^2 ~0.1 GeV^2.\nA consistent picture emerges when several measurements at about the same Q^2\nvalue are combined: G_E^s is consistent with zero while G_M^s prefers positive\nvalues though G_E^s=G_M^s=0 is compatible with the data at 95% C.L.", + "category": "nucl-ex" + }, + { + "text": "Strange Particles and Neutron Stars - Experiments at Gsi: Experiments on strangeness production in nucleus-nucleus collisions at SIS\nenergies address fundamental aspects of modern nuclear physics: the\ndetermination of the nuclear equation-of-state at high baryon densities and the\nproperties of hadrons in dense nuclear matter. Experimental data and\ntheoretical results will be reviewed. Future experiments at the FAIR\naccelerator aim at the exploration of the QCD phase diagram at highest baryon\ndensities.", + "category": "nucl-ex" + }, + { + "text": "Determination of quadrupole strengths in the gamma*p-->Delta(1232)\n transition at Q2= 0.20 (GeV/c)2: We report new precise p$(\\vec{e},e^\\prime p)\\pi^0$ measurements at the peak\nof the $\\Delta^{+}(1232)$ resonance at $Q^2=\\unit[0.20](GeV/c)^2$ performed at\nthe Mainz Microtron (MAMI). The new data are sensitive to both the electric\nquadrupole ($E2$) and the coulomb quadrupole ($C2$) amplitudes of the $\\gamma^*\nN\\to\\Delta$ transition. They yield precise quadrupole to dipole amplitude\nratios CMR $= (-5.09 \\pm 0.28_{stat+sys}\\pm 0.30_{model})%$ and EMR $= (-1.96\n\\pm 0.68_{stat+sys} \\pm 0.41_{model})%$ for $M^{3/2}_{1+} = (39.57 \\pm\n0.75_{stat+sys}\\pm 0.40_{model})(10^{-3}/m_{\\pi^+})$. The new results are in\ndisagreement with Constituent Quark Model predictions and in qualitative\nagreement with models that account for mesonic contributions, including recent\nLattice calculations. They thus give further credence to the conjecture of\ndeformation in hadronic systems favoring the attribution of the origin of\ndeformation to the dominance of mesonic effects.", + "category": "nucl-ex" + }, + { + "text": "Measurements of ${\u039b_{\\rm c}^+\\rm /D^0}$ ratio as a function of\n multiplicity at midrapidity at $ \\sqrt{s_{\\text{NN}}} = 5.02\\; \\text{TeV}$: In this contribution, the measurement of prompt ${\\Lambda_{\\rm c}^+\\rm /D^0}$\nratio as a function of multiplicity in p--Pb collisions at mid-rapidity at $\n\\sqrt{s_{\\text{NN}}} = 5.02 \\;\\text{TeV}$ is discussed. By performing this\nmeasurement as a function of multiplicity in pp and p--Pb collisions, we can\nevaluate the $p_{\\rm T}$-differential baryon to meson enhancement and compare\nthem to results in $ \\rm e^-e^+$ and $ \\rm e^-p$ collisions, where lower\n${\\Lambda_{\\rm c}^+\\rm /D^0}$ ratios at low and intermediate $p_{\\rm T}$ have\nbeen observed, with the origin of this different behavior being still debated.\nIn these measurements, we aim to compare the p--Pb results to pp collisions to\ninvestigate the possible effects of cold nuclear matter on charm-baryon\nproduction, and to Pb--Pb collisions for investigating the impact of\nquark--gluon plasma on charm quark hadronization.", + "category": "nucl-ex" + }, + { + "text": "Strangeness and bulk freeze-out properties at RHIC: Identified charged kaon, pion, and proton spectra and ratios from sqrt(s_NN)\n= 200 and 62.4 GeV Cu+Cu collisions are studied with a hydro-motivated\nblast-wave and a statistical model framework in order to explore the\nstrangeness production at RHIC and characterize the bulk freeze-out properties\nof the created system. The spectra are measured at mid-rapidity |y|<0.1 over\nthe transverse momentum range of 0.25 < p_T < 1.2 GeV/c with particle\nidentification derived from the ionization energy loss in the STAR Time\nProjection Chamber.\n The multi-dimensional systematic study of pi(+/-), K(+/-), p and pbar\nproduction in Cu+Cu, Au+Au, d+Au and p+p collisions is used to discuss the\nenergy, system size and inferred energy density dependence of freeze-out\nparameters and strangeness production. The new data from Cu+Cu collisions\nbridge the gap between the smaller d+Au and larger Au+Au systems, allowing a\ndetailed study of the onset of strangeness equilibration at RHIC.", + "category": "nucl-ex" + }, + { + "text": "A radium assay technique using hydrous titanium oxide adsorbent for the\n Sudbury Neutrino Observatory: As photodisintegration of deuterons mimics the disintegration of deuterons by\nneutrinos, the accurate measurement of the radioactivity from thorium and\nuranium decay chains in the heavy water in the Sudbury Neutrino Observatory\n(SNO) is essential for the determination of the total solar neutrino flux. A\nradium assay technique of the required sensitivity is described that uses\nhydrous titanium oxide adsorbent on a filtration membrane together with a\nbeta-alpha delayed coincidence counting system. For a 200 tonne assay the\ndetection limit for 232Th is a concentration of 3 x 10^(-16) g Th/g water and\nfor 238U of 3 x 10^(-16) g U/g water. Results of assays of both the heavy and\nlight water carried out during the first two years of data collection of SNO\nare presented.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal anisotropy measurements of strange and multistrange hadrons in\n U+U collisions at $\\sqrt{s_{NN}} = 193$ GeV at the BNL Relativistic Heavy Ion\n Collider: We present systematic measurements of azimuthal anisotropy for strange and\nmultistrange hadrons ($K^{0}_{s}$, $\\Lambda$, $\\Xi$, and $\\Omega$) and $\\phi$\nmesons at midrapidity ($|y| <$ 1.0) in collisions of U + U nuclei at\n$\\sqrt{s_{NN}} = 193$ GeV, recorded by the STAR detector at the Relativistic\nHeavy Ion Collider. Transverse momentum ($p_{\\text{T}}$) dependence of flow\ncoefficients ($v_{2}$, $v_{3}$, and $v_{4}$) is presented for minimum bias\ncollisions and three different centrality intervals. Number of constituent\nquark scaling of the measured flow coefficients in U + U collisions is\ndiscussed. We also present the ratio of $v_{n}$ scaled by the participant\neccentricity ($\\varepsilon_{n}\\left\\lbrace 2 \\right\\rbrace$) to explore system\nsize dependence and collectivity in U + U collisions. The magnitude of\n$v_{2}/\\varepsilon_{2}$ is found to be smaller in U + U collisions than that in\ncentral Au + Au collisions contradicting naive eccentricity scaling.\nFurthermore, the ratios between various flow harmonics ($v_{3}/v_{2}^{3/2}$,\n$v_{4}/v_{2}^{4/2}$) are studied and compared with hydrodynamic and transport\nmodel calculations.", + "category": "nucl-ex" + }, + { + "text": "New Experimental Limits on Exotic Spin- and Velocity-dependent\n Interactions Using Rotationally Modulated Source-masses and an\n Atomic-magnetometer Array: We conducted laboratory searching for the exotic spin- and velocity-dependent\nnew interactions according to the previously proposed experimental scheme. Two\n$\\sim$6Kg heavy source masses are rotationally modulated at a frequency of\n20Hz. Four identical atomic magnetometers are used in an array form to increase\nthe statistics and cancel the common-mode noise. Data processing method based\non high precision numerical integration is applied for the four harmonic\nfrequencies of the signal. The rotation direction of the source masses was\nreversed to flip the signal. Thus the [1,-3,3,-1] weighting method can be\napplied to remove possible slow drifting further. The experiment method has\nnoise reduction features, and new constraints for Vector-Axial and Axial-Axial\nwere obtained. The new constraints on VA improved by as much as more than four\norders, on AA by as much as two orders in the corresponding force range,\nrespectively.", + "category": "nucl-ex" + }, + { + "text": "The RHIC Beam Energy Scan Phase II: Physics and Upgrades: The exploration of the QCD phase diagram has been one of the main drivers of\ncontemporary nuclear physics. The Relativistic Heavy Ion Collider (RHIC) at BNL\nis uniquely suited for this task through its Beam Energy Scan (BES) program\nwhich allowed for a large range in baryon chemical potential $\\mu_B$ as was\nsuccessfully demonstrated after the completion of Phase 1 in 2014. Phase 2 of\nthe BES at RHIC is scheduled to start in 2019 and will explore with precision\nmeasurements the intermediate-to-high $\\mu_B$ region of the QCD phase diagram,\nfive energies $\\sqrt{s_{NN}}$ from 7.7 to 19.6 GeV in collider mode and eight\nenergies $\\sqrt{s{_{NN}}}$ from 3.0 to 7.7 GeV in fixed-target mode. Some of\nthe key measurements are: the net-protons kurtosis that could pinpoint the\nposition of a critical point, the directed flow that might prove a softening of\nthe EOS, and the chiral restoration in the dielectron channel. These\nmeasurements will be possible with an order of magnitude better statistics\nprovided by the electron cooling upgrade of RHIC and with the detector upgrades\nplanned to improve STAR's acceptance. These proceedings review the BES Phase-2\nprogram and the physics opportunities enabled by these upgrades.", + "category": "nucl-ex" + }, + { + "text": "Beyond the Neutron Drip-Line: The Unbound Oxygen Isotopes 25O and 26O: The very neutron-rich oxygen isotopes 25O and 26O are investigated\nexperimentally and theoret- ically. In this first R3B-LAND experiment, the\nunbound states are populated at GSI via proton- knockout reactions from 26F and\n27F at relativistic energies around 450 MeV/nucleon. From the kinematically\ncomplete measurement of the decay into 24O plus one or two neutrons, the 25O\nground- state energy and lifetime are determined, and upper limits for the 26O\nground state are extracted. In addition, the results provide evidence for an\nexcited state in 26O at around 4 MeV. The ex- perimental findings are compared\nto theoretical shell-model calculations based on chiral two- and three-nucleon\n(3N) forces, including for the first time residual 3N forces, which are shown\nto be amplified as valence neutrons are added.", + "category": "nucl-ex" + }, + { + "text": "Differential Elliptic Flow in 2 - 6 AGeV Au+Au Collisions: A New\n Constraint for the Nuclear Equation of State: Proton elliptic flow is studied as a function of impact-parameter $b$, for\ntwo transverse momentum cuts in 2 - 6 AGeV Au + Au collisions. The elliptic\nflow shows an essentially linear dependence on b (for $1.5 < b < 8$ fm) with a\nnegative slope at 2 AGeV, a positive slope at 6 AGeV and a near zero slope at 4\nAGeV. These dependencies serve as an important constraint for discriminating\nbetween various equations of state (EOS) for high density nuclear matter, and\nthey provide important insights on the interplay between collision geometry and\nthe expansion dynamics. Extensive comparisons of the measured and calculated\ndifferential flows provide further evidence for a softening of the EOS between\n2 and 6 GeV/nucleon.", + "category": "nucl-ex" + }, + { + "text": "Radioactive Ion Beam Physics and Nuclear Astrophysics in China: Based on the intermediate energy radioactive Ion Beam Line in Lanzhou (RIBLL)\nof Heavy Ion Research Facility in Lanzhou (HIRFL) and Low Energy Radioactive\nIon Beam Line (GIRAFFE) of Beijing National Tandem Accelerator Lab (HI13), the\nradioactive ion beam physics and nuclear astrophysics will be researched in\ndetail. The key scientific problems are: the nuclear structure and reaction for\nnuclear far from $\\beta$-stability line; the synthesize of new nuclides near\ndrip lines and new super heavy nuclides; the properties of asymmetric nuclear\nmatter with extra large isospin and some nuclear astro- reactions.", + "category": "nucl-ex" + }, + { + "text": "Symmetry energy and density: The nuclear equation-of-state is a topic of highest current interest in\nnuclear structure and reactions as well as in astrophysics. In particular, the\nequation-of-state of asymmetric matter and the symmetry energy representing the\ndifference between the energy densities of neutron matter and of symmetric\nnuclear matter are not sufficiently well constrained at present. The density\ndependence of the symmetry energy is conventionally expressed in the form of\nthe slope parameter L describing the derivative with respect to density of the\nsymmetry energy at saturation. Results deduced from nuclear structure and\nheavy-ion reaction data are distributed around a mean value L=60 MeV.\n Recent studies have more thoroughly investigated the density range that a\nparticular observable is predominantly sensitive to. Two thirds of the\nsaturation density is a value typical for the information contained in\nnuclear-structure data. Higher values exceeding saturation have been shown to\nbe probed with meson production and collective flows at incident energies in\nthe range of up to about 1 GeV/nucleon.\n From the measurement of the elliptic-flow ratio of neutrons with respect to\nlight charged particles in recent experiments at the GSI laboratory, a new more\nstringent constraint for the symmetry energy at suprasaturation density has\nbeen deduced. It confirms, with a considerably smaller uncertainty, the\nmoderately soft to linear density dependence of the symmetry energy previously\ndeduced from the FOPI-LAND data. Future opportunities offered by FAIR will be\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the azimuthal anisotropy of charged-particle production\n in Xe+Xe collisions at $\\sqrt{s_{\\mathrm{NN}}}=5.44$ TeV with the ATLAS\n detector: This paper describes the measurements of flow harmonics $v_2$-$v_6$ in 3\n$\\mu\\mathrm{b}^{-1}$ of Xe+Xe collisions at $\\sqrt{s_{\\mathrm{NN}}}=5.44$ TeV\nperformed using the ATLAS detector at the LHC. Measurements of the centrality,\nmultiplicity and $p_{\\mathrm{T}}$ dependence of the $v_n$ obtained using\ntwo-particle correlations and the scalar product technique are presented. The\nmeasurements are also performed using a template-fit procedure, which was\ndeveloped to remove non-flow correlations in small collision systems. This\nnon-flow removal is shown to have a significant influence on the measured $v_n$\nat high $p_{\\mathrm{T}}$, especially in peripheral events. Comparisons of the\nmeasured $v_n$ with measurements in Pb+Pb collisions and $p$+Pb collisions at\n$\\sqrt{s_{\\mathrm{NN}}}=5.02$ TeV are also presented. The $v_n$ values in Xe+Xe\ncollisions are observed to be larger than those in Pb+Pb collisions for $n=2$,\n3 and 4 in the most central events. However, with decreasing centrality or\nincreasing harmonic order $n$, the $v_n$ values in Xe+Xe collisions become\nsmaller than those in Pb+Pb collisions. The $v_n$ in Xe+Xe and Pb+Pb collisions\nare also compared as a function of the mean number of participating nucleons,\n$\\langle N_\\text{part} \\rangle$, and the measured charged-particle multiplicity\nin the detector. The $v_3$ values in Xe+Xe and Pb+Pb collisions are observed to\nbe similar at the same $\\langle N_\\text{part}\\rangle$ or multiplicity, but the\nother harmonics are significantly different. Comparisons of the $v_n$\nmeasurements with theoretical calculations are also made.", + "category": "nucl-ex" + }, + { + "text": "Systematic study of symmetric cumulants at $\\sqrt{s_{NN}}$ = 200 GeV in\n Au+Au collision using transport approach: Measurement of 4-particle symmetric cumulants has been considered to be a\ngood tool to study the correlations between amplitudes of different orders of\nanisotropic flow harmonics in the heavy-ion collision. These new observables\nnot yet been measured at RHIC. Using A Multi-Phase Transport model, a set of\npredictions for the centrality dependence of the normalized 4-particle\nsymmetric cumulants in Au+Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV has been\ngiven. In addition, the effects of shear viscosity and hadronic rescattering on\nthe magnitude of symmetric cumulants are discussed using AMPT model at\n$\\sqrt{s_{NN}}$ = 200 GeV. It is shown that $sc(2,3)$ is found to be more\nsensitive to hadronic rescattering, whereas $sc(2,4)$ is more sensitive to the\nshear viscosity. Rapidity dependence of symmetric cumulants is also shown. A\nrelation between symmetric cumulant and event plane correlation is investigated\nusing AMPT model.", + "category": "nucl-ex" + }, + { + "text": "Particle Production in Au+Au Collisions at $\\sqrt{s_{NN}}$ = 9.2 GeV: In this report we present the first test run results from Au+Au collisions at\n$\\sqrt{s_{NN}}$ = 9.2 GeV at RHIC. The large acceptance STAR detector has\ncollected ~3k minimum bias collisions during this test run. The azimuthal\nanisotropy, identified particle spectra, particle ratios and HBT radii are\nobserved to be consistent with the previous measurements from CERN SPS at\nsimilar center of mass energies. These results from the lowest collision energy\nat RHIC demonstrate the STAR detector's readiness to collect high quality data\nfor the proposed Critical Point Search Program which allows us to explore the\nQCD phase diagram.", + "category": "nucl-ex" + }, + { + "text": "Dynamical kurtosis of net and total proton distributions in STAR at RHIC: We report the energy and centrality dependence of dynamical kurtosis for Au +\nAu collisions at $\\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV at\nRHIC. The dynamical kurtosis of net-proton is compared to that of total-proton.\nThe results are also compared with AMPT model calculations.", + "category": "nucl-ex" + }, + { + "text": "Studies of the equation-of-state of nuclear matter by heavy-ion\n collisions at intermediate energy in the multi-messenger era: The study of the equation-of-state (EoS) describing the properties of nuclear\nmatter away from the normal conditions is a relevant and intriguing topic of\nmodern nuclear physics. The last decades have witnessed a substantial\nexperimental progress in derivation of the symmetric matter term of the EoS and\nof the so-called symmetry energy for the asymmetric matter, especially at\ndensities below the saturation point. But it is only in recent years that the\nopening of the multi-messenger astronomy era, triggered by detection of\ngravitational waves due to the neutron star mergers, has renewed and enlarged\nthe interest in high-density EoS, being the main ingredient for determining the\nstructure and properties of neutron stars. In this paper we review our\nknowledge obtained from heavy-ion collisions up to the 1 GeV/nucleon regime, on\nthe EoS above nuclear saturation density. Special emphasis is given on the\nstill few results on symmetry energy at high densities and their\ninterconnections with multi-messenger astronomy findings.", + "category": "nucl-ex" + }, + { + "text": "Global polarization of $\u039b$ hyperons in Au+Au collisions at\n $\\sqrt{s_{_{NN}}}$ = 200 GeV: Global polarization of $\\Lambda$ hyperons has been measured to be of the\norder of a few tenths of a percent in Au+Au collisions at $\\sqrt{s_{_{NN}}}$ =\n200 GeV, with no significant difference between $\\Lambda$ and $\\bar{\\Lambda}$.\nThese new results reveal the collision energy dependence of the global\npolarization together with the results previously observed at\n$\\sqrt{s_{_{NN}}}$ = 7.7 -- 62.4 GeV and indicate noticeable vorticity of the\nmedium created in non-central heavy-ion collisions at the highest RHIC\ncollision energy. The signal is in rough quantitative agreement with the\ntheoretical predictions from a hydrodynamic model and from the AMPT (A\nMulti-Phase Transport) model. The polarization is larger in more peripheral\ncollisions, and depends weakly on the hyperon's transverse momentum and\npseudorapidity $\\eta^H$ within $|\\eta^H|<1$. An indication of the polarization\ndependence on the event-by-event charge asymmetry is observed at the $2\\sigma$\nlevel, suggesting a possible contribution to the polarization from the axial\ncurrent induced by the initial magnetic field.", + "category": "nucl-ex" + }, + { + "text": "Flow-plane decorrelations in heavy-ion collisions with multiple-plane\n cumulants: The azimuthal correlations between local flow planes at different\n(pseudo)rapidities ($\\eta$) may reveal important details of the initial nuclear\nmatter density distributions in heavy-ion collisions. Extensive experimental\nmeasurements of a factorization ratio ($r_2$) and its derivative ($F_2$) have\nshown evidence of the longitudinal flow-plane decorrelation. However, nonflow\neffects also affect this observable and prevent a quantitative understanding of\nthe phenomenon. In this paper, to distinguish decorrelation and nonflow\neffects, we propose a new cumulant observable, $T_2$, which largely suppresses\nnonflow. The technique sensitivity to different initial-state scenarios and\nnonflow effects are tested with a simple Monte Carlo model, and in the end, the\nmethod is applied to events simulated by a multiphase transport model (AMPT)\nfor Au+Au collisions at $\\sqrt{s_{\\rm NN}} =200$ GeV. We also emphasize that a\ndistinct decorrelation signal requires not only the right sign of an\nobservable, but also its proper dependence on the $\\eta$-window of the\nreference flow plane, to be consistent with the pertinent decorrelation\npicture.", + "category": "nucl-ex" + }, + { + "text": "Study of $^{26}$Mg through 1p pick up reaction $^{27}$Al(d,$^{3}$He): The even-even nucleus $^{26}$Mg has been studied through the reaction\n$^{27}$Al(d,$^{3}$He) at 25 MeV beam energy. The spectroscopic factors have\nbeen extracted upto 7.50 MeV excitation energy using local, zero range\ndistorted wave Born approximation. The comparison of the spectroscopic factors\nhave been done with previously reported values using the same reaction probe.\nThe extracted spectroscopic factors for different excited states were found to\nbe in good agreement with the previously reported values for the same. The\npresent results were also compared with the predictions from shell model as\nwell as rotational model. The analog states of $^{26}$Al and $^{26}$Mg were\nfound to be in good agreement.", + "category": "nucl-ex" + }, + { + "text": "Survival Mediated Heavy Element Capture Cross Sections: Formally, the cross section for producing a heavy evaporation residue,\n{\\sigma}EVR, in a fusion reaction can be written as. \\begin{equation}\n\\sigma_{\\rm EVR}(E)=\\frac{\\pi h^2}{2\\mu E}\\sum\\limits_{\\ell=0}^\\infty\n(2\\ell+1)T(E,\\ell)P_{\\rm CN}(E,\\ell)W_{\\rm sur}(E,\\ell), \\end{equation} where E\nis the center of mass energy, and T is the probability of the colliding nuclei\nto overcome the potential barrier in the entrance channel and reach the contact\npoint. PCN is the probability that the projectile-target system will evolve\nfrom the contact point to the compound nucleus. Wsur is the probability that\nthe compound nucleus will decay to produce an evaporation residue rather than\nfissioning. However, one must remember that the Wsur term effectively sets the\nallowed values of the spin, which in turn, restricts the values of the capture\nand fusion cross sections. We point out the implications of this fact for\ncapture cross sections for heavy element formation reactions.", + "category": "nucl-ex" + }, + { + "text": "Half-Life of $^{14}$O: We have measured the half-life of $^{14}$O, a superallowed $(0^{+} \\to\n0^{+})$ $\\beta$ decay isotope. The $^{14}$O was produced by the\n$^{12}$C($^{3}$He,n)$^{14}$O reaction using a carbon aerogel target. A\nlow-energy ion beam of $^{14}$O was mass separated and implanted in a thin\nberyllium foil. The beta particles were counted with plastic scintillator\ndetectors. We find $t_{1/2} = 70.696\\pm 0.052$ s. This result is $1.5\\sigma$\nhigher than an average value from six earlier experiments, but agrees more\nclosely with the most recent previous measurement.", + "category": "nucl-ex" + }, + { + "text": "Discovery of Long-Lived Shape Isomeric States which Decay by Strongly\n Retarded High-Energy Particle Radioactivity: The reaction 28Si + 181Ta has been studied at E(Lab) = 125 and 135 MeV.\nCoincidences between high energy particles and various X- and gamma-rays from\nabnormally long-lived states were observed. e.g. 7.8 - 8.6 MeV alpha-particles\nwith gamma-rays of a superdeformed band, 5.1 - 5.5 MeV alpha-particles with X-\nand gamma-rays of W, Re, and Pt, and 3.88 MeV particles (interpreted as\nprotons) with 185.8 keV gamma-rays. The data are interpreted in terms of the\nproduction of long-lived (t(1/2) of several months) high spin isomeric states\nin the second well of the potential in the parent nuclei, which decay to the\nnormal states in the daughters, and in the third well of the potential, which\ndecay to the second well.", + "category": "nucl-ex" + }, + { + "text": "J/$\u03c8$ polarization in p+p collisions at $\\sqrt{s}$ = 200 GeV in STAR: In this paper, J/$\\psi$ polarization at mid-rapidity in $p+p$ collisions at\n$\\sqrt{s}$ = 200 GeV measured in the STAR experiment at RHIC is reported.\nJ/$\\psi$ production is analyzed via the dielectron decay channel. J/$\\psi$\npolarization is extracted from the decay angular distribution in the helicity\nframe. The J/$\\psi$ polarization is measured at transverse momentum range (2 -\n6) GeV/c and is found to be consistent with $NLO^+$ Color Singlet Model\n($NLO^+$ CSM), Color Octet Model (COM) predictions and with no polarization\nwithin current uncertainties.", + "category": "nucl-ex" + }, + { + "text": "Masses of ground and isomeric states of $^{101}$In and\n configuration-dependent shell evolution in odd-$A$ indium isotopes: We report first precision mass measurements of the $1/2^-$ isomeric and\n$9/2^+$ ground states of $^{101}$In. The determined isomeric excitation energy\ncontinues a smooth trend of odd-$A$ indium isotopes up to the immediate\nvicinity of $N=50$ magic number. This trend can be confirmed by dedicated shell\nmodel calculations only if the neutron configuration mixing is considered. We\nfind that the single particle energies are different for different states of\nthe same isotope. The presented configuration-dependent shell evolution, type\nII shell evolution, in odd-$A$ nuclei is discussed for the first time. Our\nresults will facilitate future studies of single-particle neutron states.", + "category": "nucl-ex" + }, + { + "text": "Estimation of double differential angle-dependent neutron production\n cross sections from tritons on 197Au at energies from 5.97 to 19.14 MeV: Estimated cross sections for neutron production from triton bombardment of\ngold are deduced from measurements of triton interactions with gas targets that\nused gold as a triton beam stop material. Differential cross sections for\nproduction of neutrons from 5.97-, 7.47-, 10.45-, 16.41- and 19.14-MeV tritons\non 197Au were evaluated. Corrections for the neutron interaction in gold, in\nthe target structure and in the air of the flight path were obtained by means\nof a Monte Carlo technique. Uncorrelated scale uncertainties range from 24 to\n41% whereas those of double differential cross sections range from 0.2 to 5%.\nBased on these cross section data, calculation of neutron yield at 0o from\nfully stopped tritons at 20.22 MeV agree with an independent measurement.\nLeast-squares fits with a gamma distribution model indicate an anisotropy in\nthe high energy portion of the neutron spectra. Legendre polynomial fits of\ndifferential cross sections are reported. All neutron cross section data are\nmade available through the Experimental Nuclear Reaction Data (EXFOR) library\nat international data centers.", + "category": "nucl-ex" + }, + { + "text": "Radial position of single-site gamma-ray interactions from a parametric\n pulse shape analysis of germanium detector signals: Pulse shape analysis of germanium gamma-ray spectrometer signals can yield\ninformation on the radial position of individual gamma-ray interactions within\nthe germanium crystal. A parametric pulse shape analysis based on calculation\nof moments of the reconstructed current pulses from a closed-ended coaxial\ngermanium detector is used to preferentially select single-site gamma-ray\ninteractions. The double escape peak events from the 2614.5 keV gamma-ray of\n208-Tl are used as a training set to optimize the single-site event selection\nregion in the pulse shape parameter space. A collimated source of 320.1 keV\ngamma-rays from 51-Cr is used to scan different radial positions of the same\nsemi-coaxial germanium detector. The previously trained single-site selection\nregion is used to preferentially identify the single-site photoelectric\nabsorption events from the 320.1 keV full-energy peak. From the identified\nevents, a comparison of the pulse shape parameter space distributions between\ndifferent scan positions allows radial interaction location information to be\ncollected.", + "category": "nucl-ex" + }, + { + "text": "Anisotropy Scaling Functions in Heavy-Ion Collisions: Insights into the\n `Ultra-Central Flow Puzzle' and Constraints on Transport Coefficients and\n Nuclear Deformation: Anisotropy scaling functions, derived from extensive measurements of\ntransverse momentum- and centrality-dependent anisotropy coefficients\n$v_2(p_T,\\text{cent})$ and $v_3(p_T,\\text{cent})$ in Pb+Pb collisions at 5.02\nand 2.76 TeV, and Xe+Xe collisions at 5.44 TeV at the LHC, shed light on the\n'ultra-central flow puzzle'. These functions amalgamate diverse measurements\ninto a unified curve, elucidating anisotropy attenuation across the full $p_T$\nand centrality range and unveiling dependencies on key factors including\ninitial-state eccentricities ($\\varepsilon_{n}$), dimensionless size\n($\\mathbb{R}$), radial flow, viscous correction to the thermal distribution\nfunction ($\\delta_f$), the medium's stopping power ($\\hat{q}$), and specific\nshear viscosity ($\\eta/s$). Their analysis provides distinct insights into\ntransport coefficients and nucleus deformation constraints.", + "category": "nucl-ex" + }, + { + "text": "Experimental summary on global observables, hadron spectra and ratios: This article summarizes results on global observables, hadron spectra, and\nratios of integrated hadron yields as presented at the Quark Matter 2002\nConference.", + "category": "nucl-ex" + }, + { + "text": "High $p_T$ correlations of $\u03b3$ and charged hadrons at RHIC: Prompt photon production in ultra-relativistic heavy-ion collisions provides\na calibrated probe for the study of the properties of high energy density QCD\nmatter. Especially interesting are the measurements of $\\gamma$-tagged jets\nwhere the hard scattering scale is known and can be used to determine the\npartonic energy loss in the dense matter. We discuss the potential of\n$\\gamma$-jet measurements at the Relativistic Heavy Ion Collider (RHIC) and\nargue that the observed supression of the away-side correlations for di-jet\nproduction in central Au+Au collisions at $\\sqrt{s_{NN}}$=200 GeV should\nsignificantly reduce the backgrounds for the $\\gamma$-jet coincidence\nmeasurements.", + "category": "nucl-ex" + }, + { + "text": "Resonance photoproduction of pionic atoms at the Gamma Factory: We present a possibility of direct resonance production of pionic atoms\n(Coulomb bound states of a negative pion and a nucleus) with a rate of up to\n$\\sim10^{10}$ per second using the gamma-ray beams from the Gamma Factory.", + "category": "nucl-ex" + }, + { + "text": "Muonic atom spectroscopy with microgram target material: Muonic atom spectroscopy -- the measurement of the x rays emitted during the\nformation process of a muonic atom -- has a long standing history in probing\nthe shape and size of nuclei. In fact, almost all stable elements have been\nsubject to muonic atom spectroscopy measurements and the absolute charge radii\nextracted from these measurements typically offer the highest accuracy\navailable. However, so far only targets of at least a few hundred milligram\ncould be used as it required to stop a muon beam directly in the target to form\nthe muonic atom. We have developed a new method relying on repeated transfer\nreactions taking place inside a 100-bar hydrogen gas cell with an admixture of\n0.25% deuterium that allows us to drastically reduce the amount of target\nmaterial needed while still offering an adequate efficiency. Detailed\nsimulations of the transfer reactions match the measured data, suggesting good\nunderstanding of the processes taking place inside the gas mixture. As a proof\nof principle we demonstrate the method with a measurement of the 2p-1s muonic x\nrays from a 5-{\\mu}g gold target.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the Transverse Polarization of Electrons Emitted in Free\n Neutron Decay: Both components of the transverse polarization of electrons emitted in the\nbeta-decay of polarized, free neutrons have been measured. The T-odd, P-odd\ncorrelation coefficient quantifying the component perpendicular to the decay\nplane defined by neutron polarization and electron momentum, was found to be\nR=0.008 +/- 0.015 +/-0.005. This value is consistent with time reversal\ninvariance, and significantly improves limits on the relative strength of\nimaginary scalar couplings in the weak interaction. The value obtained for the\ncorrelation coefficient associated with the electron polarization component\ncontained within the decay plane N=0.056 +/- 0.011 +/- 0.005, agrees with the\nStandard Model expectation, providing an important sensitivity test of the\nexperimental setup.", + "category": "nucl-ex" + }, + { + "text": "Observation of a multiplicity dependence in the $p_{\\rm T}$-differential\n charm baryon-to-meson ratios in proton-proton collisions at $\\sqrt{s} = 13$\n TeV: The production of prompt $D^{0}$, $D^{+}_{\\rm s}$, and $\\Lambda_{\\rm c}^{+}$\nhadrons, and their ratios, $D^{+}_{\\rm s}$/$D^{0}$ and $\\Lambda_{\\rm\nc}^{+}$/$D^{0}$, are measured in proton-proton collisions at $\\sqrt{s}$ = 13\nTeV at midrapidity ($|y| <0.5$) with the ALICE detector at the LHC. The\nmeasurements are performed as a function of the charm-hadron transverse\nmomentum ($p_{\\rm T}$) in intervals of charged-particle multiplicity, measured\nwith two multiplicity estimators covering different pseudorapidity regions.\nWhile the strange to non-strange $D^{+}_{\\rm s}$/$D^{0}$ ratio indicates no\nsignificant multiplicity dependence, the baryon-to-meson $p_{\\rm\nT}$-differential $\\Lambda_{\\rm c}^{+}$/$D^{0}$ ratio shows a\nmultiplicity-dependent enhancement, with a significance of 5.3$\\sigma$ for $1<\np_{\\rm T} < 12$ GeV/$c$, comparing the highest multiplicity interval with\nrespect to the lowest one. The measurements are compared with a theoretical\nmodel that explains the multiplicity dependence by a canonical treatment of\nquantum charges in the statistical hadronisation approach, and with predictions\nfrom event generators that implement colour reconnection mechanisms beyond the\nleading colour approximation to model the hadronisation process. The\n$\\Lambda_{\\rm c}^{+}$/$D^{0}$ ratios as a function of $p_{\\rm T}$ present a\nsimilar shape and magnitude as the $\\Lambda/K^{0}_{s}$ ratios in comparable\nmultiplicity intervals, suggesting a potential common mechanism for light- and\ncharm-hadron formation, with analogous multiplicity dependence. The $p_{\\rm\nT}$-integrated ratios, extrapolated down to $p_{\\rm T}$=0, do not show a\nsignificant dependence on multiplicity within the uncertainties.", + "category": "nucl-ex" + }, + { + "text": "Suppression of Upsilon(1S), Upsilon(2S), and Upsilon(3S) production in\n PbPb collisions at sqrt(s[NN]) = 2.76 TeV: The production yields of Upsilon(1S), Upsilon(2S), and Upsilon(3S) quarkonium\nstates are measured through their decays into muon pairs in the CMS detector,\nin PbPb and pp collisions at the centre-of-mass energy per nucleon pair of 2.76\nTeV. The data correspond to integrated luminosities of 166 inverse microbarns\nand 5.4 inverse picobarns for PbPb and pp collisions, respectively.\nDifferential production cross sections are reported as functions of Upsilon\nrapidity y up to 2.4, and transverse momentum pT up to 20 GeV/c. A strong\ncentrality-dependent suppression is observed in PbPb relative to pp collisions,\nby factors of up to approximately 2 and 8, for the Upsilon(1S) and Upsilon(2S)\nstates, respectively. No significant dependence of this suppression is observed\nas a function of y or pT. The Upsilon(3S) state is not observed in PbPb\ncollisions, which corresponds to a suppression for the centrality-integrated\ndata by at least a factor of approximately 7 at a 95% confidence level. The\nobserved suppression is in agreement with theoretical scenarios modeling the\nsequential melting of quarkonium states in a quark gluon plasma.", + "category": "nucl-ex" + }, + { + "text": "First limits on double beta decays in $^{\\bf 232}$Th: As one of the primordial radioactive isotopes, $^{232}$Th mainly undergoes\n$\\alpha$-decay with a half-life of $1.402 \\times 10^{10}$ yr. However, it is\nalso one of 35 double beta decay candidates in which the single $\\beta$-decay\nis forbidden or strongly suppressed. 181 mg of thorium contained in a gas\nmantle was measured in an HPGe well-detector at the Gran Sasso Underground\nLaboratory (LNGS) with a total exposure of 3.25 g $\\times$ d. We obtain\nhalf-life limits on all double beta decay modes of $^{232}$Th to excited states\nof $^{232}$U on the order of $10^{11-15}$ yr. For the most likely transition\ninto the $0_1^+$ state we find a lower half-life limit of $6.3 \\times 10^{14}$\nyr (90% credibility). These are the first constraints on double beta decay\nexcited state transition in $^{232}$Th.", + "category": "nucl-ex" + }, + { + "text": "Ridges in p-A (and pp) collisions: Correlations between particles separated by several units of pseudorapidity\nwere discovered in high-multiplicity pp and p-Pb collisions at the LHC. These\nlong-range structures observed in two-particle correlation functions are\nreminiscent of features seen in Pb-Pb collisions, where they are often viewed\nas a signature of collective behavior and the formation of a quark-gluon plasma\n(QGP). Therefore, the discovery of these `ridges' in small systems has\nimplications for the study of collectivity in small systems as well as in\nheavy-ion collisions. The ridges in pp and p-Pb collisions have been studied in\nthe ALICE, ATLAS, CMS, and LHCb experiments to characterize the $p_{\\rm{T}}$-,\n$\\eta$-, and multiplicity-dependences of the ridge yield, as well as its\nparticle composition.", + "category": "nucl-ex" + }, + { + "text": "The structure of 70Fe: Single-particle and collective degrees of freedom: Excited states in the neutron-rich \\nuc{70}{Fe} nucleus were populated in a\none-proton removal reaction from \\nuc{71}{Co} projectiles at 87~MeV/nucleon. A\nnew transition was observed with the $\\gamma$-ray tracking array GRETINA and\nshown to feed the previously assigned $4^+_1$ state. In comparison to reaction\ntheory calculations with shell-model spectroscopic factors, it is argued that\nthe new $\\gamma$ ray possibly originates from the $6^+_1$ state. It is further\nshown that the Doppler-reconstructed $\\gamma$-ray spectra are sensitive to the\nvery different lifetimes of the $2^+$ and $4^+$ states, enabling their\napproximate measurement. The emerging structure of \\nuc{70}{Fe} is discussed in\ncomparison to LNPS-new large-scale shell-model calculations.", + "category": "nucl-ex" + }, + { + "text": "Combined Analysis of all Three Phases of Solar Neutrino Data from the\n Sudbury Neutrino Observatory: We report results from a combined analysis of solar neutrino data from all\nphases of the Sudbury Neutrino Observatory. By exploiting particle\nidentification information obtained from the proportional counters installed\nduring the third phase, this analysis improved background rejection in that\nphase of the experiment. The combined analysis resulted in a total flux of\nactive neutrino flavors from 8B decays in the Sun of (5.25 \\pm\n0.16(stat.)+0.11-0.13(syst.))\\times10^6 cm^{-2}s^{-1}. A two-flavor neutrino\noscillation analysis yielded \\Deltam^2_{21} = (5.6^{+1.9}_{-1.4})\\times10^{-5}\neV^2 and tan^2{\\theta}_{12}= 0.427^{+0.033}_{-0.029}. A three-flavor neutrino\noscillation analysis combining this result with results of all other solar\nneutrino experiments and the KamLAND experiment yielded \\Deltam^2_{21} =\n(7.41^{+0.21}_{-0.19})\\times10^{-5} eV^2, tan^2{\\theta}_{12} =\n0.446^{+0.030}_{-0.029}, and sin^2{\\theta}_{13} =\n(2.5^{+1.8}_{-1.5})\\times10^{-2}. This implied an upper bound of\nsin^2{\\theta}_{13} < 0.053 at the 95% confidence level (C.L.).", + "category": "nucl-ex" + }, + { + "text": "Improved Limit on Neutrinoless Double-Beta Decay in $^{130}$Te with\n CUORE: We report new results from the search for neutrinoless double-beta decay in\n$^{130}$Te with the CUORE detector. This search benefits from a four-fold\nincrease in exposure, lower trigger thresholds and analysis improvements\nrelative to our previous results. We observe a background of\n$(1.38\\pm0.07)\\cdot10^{-2}$ counts$/($keV$\\cdot$kg$\\cdot$yr$)$ in the\n$0\\nu\\beta\\beta$ decay region of interest and, with a total exposure of 372.5\nkg$\\cdot$yr, we attain a median exclusion sensitivity of $1.7\\cdot10^{25}$ yr.\nWe find no evidence for $0\\nu\\beta\\beta$ decay and set a $90\\%$ CI Bayesian\nlower limit of $3.2\\cdot10^{25}$ yr on the $^{130}$Te half-life for this\nprocess. In the hypothesis that $0\\nu\\beta\\beta$ decay is mediated by light\nMajorana neutrinos, this results in an upper limit on the effective Majorana\nmass of 75-350 meV, depending on the nuclear matrix elements used.", + "category": "nucl-ex" + }, + { + "text": "Ratios of 15N/12C and 4He/12C inclusive electroproduction cross sections\n in the nucleon resonance region: The (W,Q2)-dependence of the ratio of inclusive electron scattering cross\nsections for 15N/12C was determined in the kinematic range 0.8^{1/2}|$ evaluated from the isotope shift indicates the\ngradual shape change to spherical shape of platinum isotopes with increasing\nneutron number toward $N=$ 126.", + "category": "nucl-ex" + }, + { + "text": "Investigation of alpha-induced reactions on 130Ba and 132Ba and their\n importance for the synthesis of heavy p nuclei: Captures of alpha particles on the proton-richest Barium isotope, 130Ba, have\nbeen studied in order to provide cross section data for the modeling of the\nastrophysical gamma process. The cross sections of the 130Ba(alpha,gamma)134Ce\nand 130Ba(alpha,n)133Ce reactions have been measured with the activation\ntechnique in the center-of mass energy range between 11.6 and 16 MeV, close\nabove the astrophysically relevant energies. As a side result, the cross\nsection of the 132Ba(alpha,n)135Ce reaction has also been measured. The results\nare compared with the prediction of statistical model calculations, using\ndifferent input parameters such as alpha+nucleus optical potentials. It is\nfound that the (alpha,n) data can be reproduced employing the standard\nalpha+nucleus optical potential widely used in astrophysical applications.\nAssuming its validity also in the astrophysically relevant energy window, we\npresent new stellar reaction rates for 130Ba(alpha,gamma)134Ce and\n132Ba(alpha,gamma)136Ce and their inverse reactions calculated with the SMARAGD\nstatistical model code. The highly increased 136Ce(gamma,alpha)132Ba rate\nimplies that the p nucleus 130Ba cannot directly receive contributions from the\nCe isotopic chain. Further measurements are required to better constrain this\nresult.", + "category": "nucl-ex" + }, + { + "text": "High-resolution (p,t) reaction measurements as spectroscopic tests of\n {\\it ab-initio} theory in the mid $pf$-shell: Detailed spectroscopic measurements of excited states in $^{50}$Cr and\n$^{62}$Zn were performed using 24~MeV (p,t) transfer reactions on $^{52}$Cr and\n$^{64}$Zn, respectively. In total, forty-five states in $^{50}$Cr and\nsixty-seven states in $^{62}$Zn were observed up to excitation energies of\n5.5~MeV, including several previously unobserved states. These experimental\nresults are compared to {\\it ab-initio} shell-model calculations using chiral\neffective field theory ($\\chi$-EFT) with the valence-space in-medium similarity\nrenormalization group (VS-IMSRG) method. This comparison demonstrates good\nagreement in the level orderings with these new theoretical methods, albeit\nwith a slight over binding in the calculations. This work is part of a\ncontinued push to benchmark {\\it ab-initio} theoretical techniques to nuclear\nstructure data in $0^+\\rightarrow0^+$ superallowed Fermi $\\beta$ decay systems.", + "category": "nucl-ex" + }, + { + "text": "Coulomb and nuclear excitations of $^{70}$Zn and $^{68}$Ni at\n intermediate energy: The reduced transition probabilities $B(E2;\n0^+_{g.s.}\\rightarrow2_1^+,2^+_2)$ in $^{70}$Zn and the full $B(E2;\n0^+_{g.s.}\\rightarrow2^+)$ strength up to S$_n$=7.79 MeV in $^{68}$Ni have been\ndetermined at the LISE/GANIL facility using the Coulomb-excitation technique at\nintermediate beam energy on a $^{208}$Pb target. The $\\gamma$ rays emitted\nin-flight were detected with an array of 46 BaF$_2$ crystals. The angles of the\ndeflected nuclei were determined in order to disentangle and extract the\nCoulomb and nuclear contributions to the excitation of the 2$^+$ states. The\nmeasured $B(E2; 0^+_{g.s.}\\rightarrow2_1^+)$ of 1432(124) e$^2$fm$^4$ for\n$^{70}$Zn falls in the lower part of the published values which clustered\neither around 1600 or above 2000 e$^2$fm$^4$, while the $B(E2;\n0^+_{g.s.}\\rightarrow2^+_2)$ of 53(7) e$^2$fm$^4$ agrees very well with the two\npublished values. The relatively low $B(E2; 0^+_{g.s.}\\rightarrow2_1^+)$ of\n301(38) e$^2$fm$^4$ for $^{68}$Ni agrees with previous studies and confirms a\nlocal magicity at $Z=28, N=40$. Combining the results of the low-energy spectra\nof $^{68}$Ni and $^{70}$Zn and their shell-model interpretations, it is\ninteresting to notice that four different shapes (spherical, oblate, prolate\nand triaxial) are present. Finally, a summed $E2$ strength of only about 150\ne$^2$fm$^4$ has been found experimentally at high excitation energy, likely due\nto proton excitations across the $Z=28$ gap. The experimental distribution of\nthis high-energy $E2$ excitation agrees with SM calculations, but its strength\nis about two times weaker.", + "category": "nucl-ex" + }, + { + "text": "Triangular flow of negative pions emitted in PbAu collisions at\n $\\sqrt{s_{NN}} = $ 17.3 GeV: Differential triangular flow, $v_3(p_T)$, of negative pions is measured at\n$\\sqrt{s_{NN}}$= 17.3 GeV around midrapidity by the CERES/NA45 experiment at\nCERN in central PbAu collisions in the range 0-30\\% with a mean centrality of\n5.5\\%. This is the first measurement as a function of transverse momentum of\nthe triangular flow at SPS energies. The $p_T$ range extends from about 0.05\nGeV/c to more than 2 GeV/c. The triangular flow magnitude, corrected for the\nHBT effects, is smaller by a factor of about 2 than the one measured by the\nPHENIX experiment at RHIC and the ALICE experiment at the LHC. Within the\nanalyzed range of central collisions no significant centrality dependence is\nobserved. The data are found to be well described by a viscous hydrodynamic\ncalculation combined with an UrQMD cascade model for the late stages.", + "category": "nucl-ex" + }, + { + "text": "Does deuteron-induced fission on actinide nuclei prevails over the\n breakup at low incident energies?: An analysis of the $^{231}$Pa$(d,3n)$$^{230}$U reaction excitation function\nat energies around the Coulomb barrier has taken into account the\npre-equilibrium and compound-nucleus cross sections corrected for the\ndeuteron-breakup decrease of the total reaction cross section, as well as the\ninelastic breakup enhancement. The analysis reveals the dominance of the\ndeuteron breakup mechanism unlike a former assessment in this respect of the\ndeuteron-induced fission process.", + "category": "nucl-ex" + }, + { + "text": "Beam Asymmetry $\\mathbf\u03a3$ for the Photoproduction of\n $\\mathbf\u03b7$ and $\\mathbf{\u03b7^{\\prime}}$ Mesons at\n $\\mathbf{E_\u03b3=8.8}$GeV: We report on the measurement of the beam asymmetry $\\Sigma$ for the reactions\n$\\vec{\\gamma}p\\rightarrow p\\eta$ and $\\vec{\\gamma}p \\rightarrow p\\eta^{\\prime}$\nfrom the GlueX experiment, using an 8.2--8.8 GeV linearly polarized tagged\nphoton beam incident on a liquid hydrogen target in Hall D at Jefferson Lab.\nThese measurements are made as a function of momentum transfer $-t$, with\nsignificantly higher statistical precision than our earlier $\\eta$\nmeasurements, and are the first measurements of $\\eta^{\\prime}$ in this energy\nrange. We compare the results to theoretical predictions based on $t$--channel\nquasi-particle exchange. We also compare the ratio of $\\Sigma_{\\eta}$ to\n$\\Sigma_{\\eta^{\\prime}}$ to these models, as this ratio is predicted to be\nsensitive to the amount of $s\\bar{s}$ exchange in the production. We find that\nphotoproduction of both $\\eta$ and $\\eta^{\\prime}$ is dominated by natural\nparity exchange with little dependence on $-t$.", + "category": "nucl-ex" + }, + { + "text": "Early onset of ground-state deformation in the neutron-deficient\n polonium isotopes: In-source resonant ionization laser spectroscopy of the even-$A$ polonium\nisotopes $^{192-210,216,218}$Po has been performed using the $6p^37s$ $^5S_2$\nto $6p^37p$ $^5P_2$ ($\\lambda=843.38$ nm) transition in the polonium atom\n(Po-I) at the CERN ISOLDE facility. The comparison of the measured isotope\nshifts in $^{200-210}$Po with a previous data set allows to test for the first\ntime recent large-scale atomic calculations that are essential to extract the\nchanges in the mean-square charge radius of the atomic nucleus. When going to\nlighter masses, a surprisingly large and early departure from sphericity is\nobserved, which is only partly reproduced by Beyond Mean Field calculations.", + "category": "nucl-ex" + }, + { + "text": "Deeply virtual Compton scattering off nuclei: Deeply virtual Compton scattering (DVCS) is the golden exclusive channel for\nthe study of the partonic structure of hadrons, within the universal framework\nof generalized parton distributions (GPDs). This paper presents the aim and\ngeneral ideas of the DVCS experimental program off nuclei at the Jefferson\nLaboratory. The benefits of the study of the coherent and incoherent channels\nto the understanding of the EMC (European Muon Collaboration) effect are\ndiscussed, along with the case of nuclear targets to access neutron GPDs.", + "category": "nucl-ex" + }, + { + "text": "A Vision for the Science of Rare Isotopes: The field of nuclear science has considerably advanced since its beginning\njust over a century ago. Today, the science of rare isotopes is on the cusp of\na new era with theoretical and computing advances complementing experimental\ncapabilities at new facilities internationally. In this article we present a\nvision for the science of rare isotope beams (RIBs). We do not attempt to cover\nthe full breadth of the field, but rather provide a perspective and address a\nselection of topics that reflect our own interests and expertise. We focus in\nparticular on systems near the drip lines, where one often finds nuclei that\nare referred to as \"exotic,\" and where the role of the \"nuclear continuum\" is\nonly just starting to be explored. An important aspect of this article is the\nattempt to highlight the crucial connections between nuclear structure and\nnuclear reactions required to fully interpret and leverage the rich data to be\ncollected in the next years at RIB facilities. Further, we connect the efforts\nin structure and reactions to key questions of nuclear astrophysics.", + "category": "nucl-ex" + }, + { + "text": "Excited states in the neutron-rich nucleus 25F: The structure of the nucleus 25F was investigated through in-beam\n{\\gamma}-ray spectroscopy of the fragmentation of 26Ne and 27,28Na ion beams.\nBased on the particle-{\\gamma} and particle-{\\gamma}{\\gamma} coincidence data,\na level scheme was constructed and compared with shell model and\ncoupled-cluster calculations. Some of the observed states were interpreted as\nquasi single-particle states built on top of the closed-shell nucleus 24O,\nwhile the others were described as states arising from coupling of a single\nproton to the 2+ core excitation of 24O.", + "category": "nucl-ex" + }, + { + "text": "Multifractal analysis of charged particle multiplicity distribution in\n the framework of Renyi entropy: A study of multifractality and multifractal specific heat has been carried\nout for the produced shower particles in nuclear emulsion detector for\n16O-AgBr, 28Si-AgBr and 32S-AgBr interactions at 4.5AGeV/c in the framework of\nRenyi entropy. Experimental results have been compared with the prediction of\nUltra Relativistic Quantum Molecular Dynamics (UrQMD) model. Our analysis\nreveals the presence of multifractality in the multiparticle production process\nin high energy nucleus-nucleus interactions. Degree of multifractality is found\nto be higher for the experimental data and it increases with the increase of\nprojectile mass. The investigation of quark-hadron phase transition in the\nmultiparticle production in 16O-AgBr, 28Si-AgBr and 32S-AgBr interactions at\n4.5 AGeV/c in the framework of Ginzburg-Landau theory from the concept of\nmultifractality has also been presented. Evidence of constant multifractal\nspecific heat has been obtained for both experimental and UrQMD simulated data.", + "category": "nucl-ex" + }, + { + "text": "The performance of thin NaI(Tl) scintillator plate for dark matter\n search: A thin (0.05cm) and wide area (5cmX5cm) NaI(Tl) scintillator was developed.\nThe performance of the thin NaI(Tl) plate, energy resolution, single\nphotoelectron energy and position sensitivity were tested. An excellent energy\nresolution of 20% (FWHM) at 60keV was obtained. The single photoelectron energy\nwas calculated to be approximately 0.42 0.02keV. Position information in the\n5cmx5cm area of the detector was also obtained by analyzing the ratio of the\nnumber of photons collected at opposite ends of the detector. The position\nresolution was obtained to be 1cm (FWHM) in the 5cmx5cm area.", + "category": "nucl-ex" + }, + { + "text": "Spin Sum Rules and the Strong Coupling Constant at large distance: We present recent results on the Bjorken and the generalized forward spin\npolarizability sum rules from Jefferson Lab Hall A and CLAS experiments,\nfocusing on the low $Q^2$ part of the measurements. We then discuss the\ncomparison of these results with Chiral Perturbation theory calculations. In\nthe second part of this paper, we show how the Bjorken sum rule with its\nconnection to the Gerasimov-Drell-Hearn sum, allows us to conveniently define\nan effective coupling for the strong force at all distances.", + "category": "nucl-ex" + }, + { + "text": "Photofission of heavy nuclei at energies up to 4 GeV: Total photofission cross sections for 238U, 235U, 233U, 237Np, 232Th, and\nnatPb have been measured simultaneously, using tagged photons in the energy\nrange Egamma=0.17-3.84 GeV. This was the first experiment performed using the\nPhoton Tagging Facility in Hall B at Jefferson Lab. Our results show that the\nphotofission cross section for 238U relative to that for 237Np is about 80%,\nimplying the presence of important processes that compete with fission. We also\nobserve that the relative photofission cross sections do not depend strongly on\nthe incident photon energy over this entire energy range. If we assume that for\n237Np the photofission probability is equal to unity, we observe a significant\nshadowing effect starting below 1.5 GeV.", + "category": "nucl-ex" + }, + { + "text": "Prospects for time reversal invariance studies with the use of five-fold\n correlation: Advantages of investigation of time reversal invariance violation with the\nuse of three-fold (P,T-odd) and five-fold (P-even,T-odd) correlations in the\ninteraction of resonance neutrons with nuclei are briefly considered. Possible\nenhancements of T-odd effects in both cases are discussed. It is shown that the\nstudy of five-fold correlation is a perspective way to test time reversal\ninvariance. Prospects to realize dynamical nuclear alignment method for\nmeasurements of five-fold correlation are described.", + "category": "nucl-ex" + }, + { + "text": "Nuclear Targets for a Precision Measurement of the Neutral Pion\n Radiative Width: A technique is presented for precision measurements of the area densities,\ndensity * T, of approximately 5% radiation length carbon and 208Pb targets used\nin an experiment at Jefferson Laboratory to measure the neutral pion radiative\nwidth. The precision obtained in the area density for the carbon target is +/-\n0.050%, and that obtained for the lead target through an x-ray attenuation\ntechnique is +/- 0.43%.", + "category": "nucl-ex" + }, + { + "text": "Mass Measurements of Neutron-Rich Gallium Isotopes Refine Production of\n Nuclei of the First r-Process Abundance Peak in Neutron Star Merger\n Calculations: We report mass measurements of neutron-rich Ga isotopes $^{80-85}$Ga with\nTRIUMF's Ion Trap for Atomic and Nuclear science (TITAN). The measurements\ndetermine the masses of $^{80-83}$Ga in good agreement with previous\nmeasurements. The masses of $^{84}$Ga and $^{85}$Ga were measured for the first\ntime. Uncertainties between $25-48$ keV were reached. The new mass values\nreduce the nuclear uncertainties associated with the production of A $\\approx$\n84 isotopes by the \\emph{r}-process for astrophysical conditions that might be\nconsistent with a binary neutron star (BNS) merger producing a blue kilonova.\nOur nucleosynthesis simulations confirm that BNS merger may contribute to the\nfirst abundance peak under moderate neutron-rich conditions with electron\nfractions $Y_e=0.35-0.38$.", + "category": "nucl-ex" + }, + { + "text": "Photoproduction of {\\boldmath{$\u03c0^{0}$}} Mesons off Protons and\n Neutrons in the Second and Third Nucleon Resonance Region: Photoproduction of mesons off quasi-free nucleons bound in the deuteron\nallows to study the electromagnetic excitation spectrum of the neutron and the\nisospin structure of the excitation of nucleon resonances. The database for\nsuch reactions is much more sparse than for free proton targets. Single $\\pi^0$\nphotoproduction off quasi-free nucleons from the deuteron was experimentally\nstudied. Nuclear effects were investigated by a comparison of the results for\nfree protons and quasi-free protons and used as a correction for the quasi-free\nneutron data. The experiment was performed at the tagged photon beam of the\nMainz MAMI accelerator for photon energies between 0.45~GeV and 1.4~GeV, using\nan almost $4\\pi$ electromagnetic calorimeter composed of the Crystal Ball and\nTAPS detectors. A complete kinematic reconstruction of the final state removed\nthe effects of Fermi motion. Reaction model predictions and PWA for $\\gamma\nn\\rightarrow n\\pi^{0}$, based on fits to data for the other isospin channels,\ndisagreed between themselves and no model provided a good description of the\nnew data. The results demonstrate clearly the importance of a measurement of\nthe fully neutral final state for the isospin decomposition of the cross\nsection. Model refits, for example from the Bonn-Gatchina analysis, show that\nthe new and the previous data for the other three isospin channels can be\nsimultaneously described when the contributions of several partial waves are\nmodified. The results are also relevant for the suppression of the higher\nresonance bumps in total photoabsorption on nuclei, which are not well\nunderstood.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal anisotropy: the higher harmonics: We report the first observations of the fourth harmonic (v_4) in the\nazimuthal distribution of particles at RHIC. The measurement was done taking\nadvantage of the large elliptic flow generated at RHIC. The integrated v_4 is\nabout a factor of 10 smaller than v_2. For the sixth (v_6) and eighth (v_8)\nharmonics upper limits on the magnitudes are reported.", + "category": "nucl-ex" + }, + { + "text": "Collection of CERES Results: Plenary talk in Quark Matter 2005, Budapest.", + "category": "nucl-ex" + }, + { + "text": "Energy Dependence of Strangeness Production in Heavy-ion Collision: An experimental overview of the energy dependence of strangeness production\nis presented. The strange hadrons are considered a good probe to study the QCD\nmatter created in relativistic nucleus-nucleus collisions. The heavy-ion\nexperiments at SPS, RHIC, and LHC have recorded a wealth of data in\nproton-proton, proton-nucleus and nucleus-nucleus collisions at several beam\nenergies. In this proceeding, I discuss the invariant yield and azimuthal\nanisotropy measurement of strange hadrons in nucleus-nucleus collisions at SPS,\nRHIC, and LHC.", + "category": "nucl-ex" + }, + { + "text": "Isoscaling and the symmetry energy in spectator fragmentation: Isoscaling and its relation to the symmetry energy in the fragmentation of\nexcited residues produced at relativistic energies were studied in two\nexperiments conducted at the GSI laboratory. The INDRA multidetector has been\nused to detect and identify light particles and fragments with Z <= 5 in\ncollisions of 12C on 112,124Sn at incident energies of 300 and 600 MeV per\nnucleon. Isoscaling is observed, and the deduced parameters decrease with\nincreasing centrality. Symmetry term coefficients, deduced within the\nstatistical description of isotopic scaling, are near gamma = 25 MeV for\nperipheral and gamma < 15 MeV for central collisions.\n In a very recent experiment with the ALADIN spectrometer, the possibility of\nusing secondary beams for reaction studies at relativistic energies has been\nexplored. Beams of 107Sn, 124Sn, 124La, and 197Au were used to investigate the\nmass and isospin dependence of projectile fragmentation at 600 MeV per nucleon.\nThe decrease of the isoscaling parameters is confirmed and extended over the\nfull fragmentation regime covered in these reactions.", + "category": "nucl-ex" + }, + { + "text": "Non-Gaussian elliptic-flow fluctuations in PbPb collisions at\n $\\sqrt{\\smash[b]{s_{_\\text{NN}}}} =$ 5.02 TeV: Event-by-event fluctuations in the elliptic-flow coefficient $v_2$ are\nstudied in PbPb collisions at $\\sqrt{s_{_\\text{NN}}} =$ 5.02 TeV using the CMS\ndetector at the CERN LHC. Elliptic-flow probability distributions ${p}(v_2)$\nfor charged particles with transverse momentum 0.3 $< p_\\mathrm{T} <$ 3.0 GeV\nand pseudorapidity $| \\eta | <$ 1.0 are determined for different collision\ncentrality classes. The moments of the ${p}(v_2)$ distributions are used to\ncalculate the $v_{2}$ coefficients based on cumulant orders 2, 4, 6, and 8. A\nrank ordering of the higher-order cumulant results and nonzero standardized\nskewness values obtained for the ${p}(v_2)$ distributions indicate non-Gaussian\ninitial-state fluctuation behavior. Bessel-Gaussian and elliptic power fits to\nthe flow distributions are studied to characterize the initial-state spatial\nanisotropy.", + "category": "nucl-ex" + }, + { + "text": "Neutral $s$ States in Loosely Bound Nuclei: In reviewing the data that has accumulated in light nuclei we find that the\nbinding energy plays a critical role in describing the variation in energy of\n$s$ states relative to other states. The behavior of states with zero angular\nmomentum within a few MeV of threshold is qualitatively different from that of\nneutron states with any other $\\ell$ value or of any proton state. This\nobservation is explored for simple Woods-Saxon potentials and is remarkably\nsuccessful in describing a wealth of experimental data for nuclei with neutron\nnumbers between 5 and 10. The lingering of neutron $s$ states just below\nthreshold is associated with the increases in radii of the neutron density\ndistributions, the neutron halos, and leads to speculations about possible\nhalos in heavier nuclei.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the neutron capture cross-section on argon: The use of argon as a detection and shielding medium for neutrino and dark\nmatter experiments has made the precise knowledge of the cross section for\nneutron capture on argon an important design and operational parameter. Since\nprevious measurements were averaged over thermal spectra and have significant\ndisagreements, a differential measurement has been performed using a\nTime-Of-Flight neutron beam and a $\\sim$4$\\pi$ gamma spectrometer. A fit to the\ndifferential cross section from $0.015-0.15$\\,eV, assuming a $1/v$ energy\ndependence, yields $\\sigma^{2200} = 673 \\pm 26 \\text{ (stat.)} \\pm 59 \\text{\n(sys.)}$\\,mb.", + "category": "nucl-ex" + }, + { + "text": "Nuclear symmetry energy: An experimental overview: The nuclear symmetry energy is a fundamental quantity important for studying\nthe structure of systems as diverse as the atomic nucleus and the neutron star.\nConsiderable efforts are being made to experimentally extract the symmetry\nenergy and its dependence on nuclear density and temperature. In this article,\nwe review experimental studies carried out up-to-date and their current status.", + "category": "nucl-ex" + }, + { + "text": "Light neutral meson production in the era of precision physics at the\n LHC: The production of light neutral mesons in different collision systems is\ninteresting for a variety of reasons: In nucleus-nucleus (AA) collisions the\nmeasurements provide important information on the energy loss of partons\ntraversing the Quark-Gluon Plasma (QGP) which is formed in heavy-ion collisions\nat the LHC. In proton--proton (pp) collisions, neutral mesons allow us to test\nwith high precision the predictions of perturbative QCD and other model\ncalculations, and also serve as a reference for pA and AA collisions. In pA\ncollisions, cold nuclear matter effects are studied. In the ALICE experiment,\nwhich is dedicated to the study of the QGP, neutral mesons can be detected via\ntheir decay to two photons. The latter can be reconstructed using the two\ncalorimeters EMCal and PHOS or via conversions in the detector material.\nCombining state-of-the-art reconstruction techniques with the large data sample\ndelivered by the LHC in Run 2 gives us the opportunity to enhance the precision\nof our measurements. In these proceedings, an overview of neutral meson\nproduction in pp, p--Pb and Pb--Pb collisions at LHC energies, as measured with\nthe ALICE detector is presented.", + "category": "nucl-ex" + }, + { + "text": "The $Q_{weak}$ Experiment: First Determination of the Weak Charge of the\n Proton: The $Q_{weak}$ Collaboration has completed a challenging measurement of the\nparity-violating asymmetry in elastic electron-proton ($\\vec{e}$p) scattering\nat the Thomas Jefferson National Accelerator Facility (Jefferson Lab). The\ninitial result reported here is extracted from the commissioning part of the\nexperiment, constituting about 4% of the full data set. The parity-violating\nasymmetry at a low momentum transfer $Q^2$=0.025 GeV$^2$ is $A_{ep}$ = -279\n$\\pm$ 35 (stat) $\\pm$ 31 (syst) ppb, which is the smallest and most precise\nasymmetry ever measured in $\\vec{e}$p scattering. This result allowed the first\ndetermination of the weak charge of the proton $Q_W^p$ from a global fit of\nparity-violating elastic scattering (PVES) results from nuclear targets, where\nearlier data at higher $Q^2$ constrain uncertainties of hadronic structure. The\nvalue extracted from the global fit is $Q_W^p$ (PVES) = 0.064 $\\pm$ 0.012, in\nagreement with the standard model prediction $Q_W^p$ (SM) = 0.0710 $\\pm$\n0.0007. The neutral weak charges of up and down quarks are extracted from a\ncombined fit of the PVES results with a previous atomic parity violation (APV)\nmeasurement on $^{133}$Cs. The analysis of the full $Q_{weak}$ data is ongoing\nand expected to yield a value for the asymmetry within 10 ppb of precision.\n Because of the suppression of $Q_W^p$, such a high precision measurement will\nplace significant constraints to models of physics beyond the standard model.", + "category": "nucl-ex" + }, + { + "text": "Experiments with polarized 3He at MAMI: Experiments with polarized 3He at MAMI have already a long tradition. The A3\ncollaboration started in 1993 with the aim to measure the electric form factor\nof the neutron. At this time MAMI was the second accelerator where experiments\nwith 3He were possible. Some years before this pilot experiment the development\nof the apparatus to polarize 3He in Mainz started. There are two techniques\nwhich allow to polarize sufficient large quantities of 3He. Both techniques\nwill be compared and the benefit of 3He for nuclear physics will be discussed.\nAn review of the experiments done so far with 3He at MAMI will be given and the\nprogress in the target development, the detector setup and the electron beam\nperformance will be pointed out.", + "category": "nucl-ex" + }, + { + "text": "Activation cross sections of proton and deuteron induced nuclear\n reactions on holmium and erbium, related to the production of $^{161}$Er and\n $^{160}$Er medical isotopes: Experimental excitation functions for long-lived products in proton induced\nreactions were measured with the activation method in the 37-65 MeV energy\nrange on natural holmium. Stacked foil irradiation technique and high\nresolution gamma spectrometry were used in order to measure cross-section data\nfor the production of $^{161}$Er, $^{160}$Er and $^{159,157}$Dy. For comparison\nof the production routes of medically related $^{161}$Er and $^{160}$Er\nradioisotopes new experimental cross section data were deduced for the\n$^{162}$Er(p,x)$^{161,160}$Er and $^{162}$Er(d,x)$^{161,160}$Er reactions by\nre-evaluating gamma-ray spectra from earlier measurements. No earlier data were\nfound in the literature for these reactions. The experimental data are compared\nwith results of TALYS theoretical code reported in TENDL-2015.", + "category": "nucl-ex" + }, + { + "text": "Study of $\u03c6$-meson production in $p$$+$Al, $p$$+$Au, $d$$+$Au, and\n $^3$He$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$ GeV: Small nuclear collisions are mainly sensitive to cold-nuclear-matter effects;\nhowever, the collective behavior observed in these collisions shows a hint of\nhot-nuclear-matter effects. The identified-particle spectra, especially the\n$\\phi$ mesons which contain strange and antistrange quarks and have a\nrelatively small hadronic-interaction cross section, are a good tool to study\nthese effects. The PHENIX experiment has measured $\\phi$ mesons in a specific\nset of small collision systems $p$$+$Al, $p$$+$Au, and $^3$He$+$Au, as well as\n$d$$+$Au [Phys. Rev. C {\\bf 83}, 024909 (2011)], at $\\sqrt{s_{_{NN}}}=200$ GeV.\nThe transverse-momentum spectra and nuclear-modification factors are presented\nand compared to theoretical-model predictions. The comparisons with different\ncalculations suggest that quark-gluon plasma may be formed in these small\ncollision systems at $\\sqrt{s_{_{NN}}}=200$ GeV. However, the volume and the\nlifetime of the produced medium may be insufficient for observing\nstrangeness-enhancement and jet-quenching effects. Comparison with calculations\nsuggests that the main production mechanisms of $\\phi$ mesons at midrapidity\nmay be different in $p$$+$Al versus $p/d/$$^3$He$+$Au collisions at\n$\\sqrt{s_{_{NN}}}=200$ GeV. While thermal quark recombination seems to dominate\nin $p/d/$$^3$He$+$Au collisions, fragmentation seems to be the main production\nmechanism in $p$$+$Al collisions.", + "category": "nucl-ex" + }, + { + "text": "The $2_1^+ \\to 3_1^+$ gamma width in $^{22}$Na and second class currents: A previous measurement of the $\\beta-\\gamma$ directional coefficient in\n$^{22}$Na $\\beta$ decay was used to extract recoil-order form factors. The data\nindicate the requirement of a significant induced-tensor matrix element for the\ndecay.This conclusion largely relies on a Standard-Model-allowed weak magnetism\nform factor which was determined using an unpublished value of the analog\n$2_1^+\\to3_1^+$ $\\gamma$ branch in $^{22}$Na, with the further assumption that\nthe transition is dominated by its isovector $M1$ component. We obtain for the\nfirst time an unambiguous determination of the $2_1^+ \\to 3_1^+$ branch in\n$^{22}$Na to be $0.45(8)\\%$. Using the Conserved Vector Current (CVC)\nhypothesis, our branch determines the weak magnetism form factor for $^{22}$Na\n$\\beta$ decay to be $|b/Ac_1| = 8.7(1.1)$. Together with the $\\beta-\\gamma$\nangular correlation coefficient, we obtain a large induced-tensor form factor\nfor the decay that continues to disagree with theoretical predictions. Two\nplausible explanations are suggested.", + "category": "nucl-ex" + }, + { + "text": "New nuclear structure features in transactinide nuclei: The structural evolution of the heavy nuclei, with Z > 82, is investigated by\nlooking at the differential variation of the two-neutron separation energies.\nIt indicates, by non-monotonous behavior at certain neutron numbers, structure\nphenomena such as major shell (N = 126) and deformed subshell (N = 152)\nclosures. Another interesting effect is observed at N ~ 142, which is very well\ncorrelated with a previously observed, intriguing behavior of quantities\nmeasured in alpha decay, such as relative branching ratios and hindrance\nfactors of excited states from the ground state band of deformed nuclei in this\nregion. Corroboration of the existing experimental data indicates another\npossible deformed subshell closure.", + "category": "nucl-ex" + }, + { + "text": "Neutron knockout of 12Be populating neutron-unbound states in 11Be: Neutron-unbound resonant states of 11Be were populated in neutron knock-out\nreactions from 12Be and identified by 10Be-n coincidence measurements. A\nresonance in the decay-energy spectrum at 80(2) keV was attributed to a highly\nexcited unbound state in 11Be at 3.949(2) MeV decaying to the 2+ excited state\nin 10Be. A knockout cross section of 15(3) mb was inferred for this 3.949(2)\nMeV state suggesting a spectroscopic factor near unity for this 0p3/2- level,\nconsistent with the detailed shell model calculations.", + "category": "nucl-ex" + }, + { + "text": "Light Baryon Spectroscopy using the CLAS Spectrometer at Jefferson\n Laboratory: Baryons are complex systems of confined quarks and gluons and exhibit the\ncharacteristic spectra of excited states. The systematics of the baryon\nexcitation spectrum is important to our understanding of the effective degrees\nof freedom underlying nucleon matter. High-energy electrons and photons are a\nremarkably clean probe of hadronic matter, providing a microscope for examining\nthe nucleon and the strong nuclear force. Current experimental efforts with the\nCLAS spectrometer at Jefferson Laboratory utilize highly-polarized frozen-spin\ntargets in combination with polarized photon beams. The status of the recent\ndouble-polarization experiments and some preliminary results are discussed in\nthis contribution.", + "category": "nucl-ex" + }, + { + "text": "Isoscalar Giant Resonance Strengths in $^{32}$S and possible excitations\n of superdeformed and $^{28}$Si + $\u03b1$ cluster bandheads: Isoscalar giant resonances and low spin states in $^{32}$S have been measured\nwith inelastic $\\alpha$ scattering at extremely forward angles including zero\ndegrees at E$_{\\alpha}$ = 386 MeV. By applying the multipole decomposition\nanalysis, various excited states are classified according to their spin and\nparities (J$^{\\pi}$), and are discussed in relation to the super deformed and\n$^{28}$Si + $\\alpha$ cluster bands.", + "category": "nucl-ex" + }, + { + "text": "Formation of dense partonic matter in relativistic nucleus-nucleus\n collisions at RHIC: Experimental evaluation by the PHENIX collaboration: Extensive experimental data from high-energy nucleus-nucleus collisions were\nrecorded using the PHENIX detector at the Relativistic Heavy Ion Collider\n(RHIC). The comprehensive set of measurements from the first three years of\nRHIC operation includes charged particle multiplicities, transverse energy,\nyield ratios and spectra of identified hadrons in a wide range of transverse\nmomenta (p_T), elliptic flow, two-particle correlations, non-statistical\nfluctuations, and suppression of particle production at high p_T. The results\nare examined with an emphasis on implications for the formation of a new state\nof dense matter. We find that the state of matter created at RHIC cannot be\ndescribed in terms of ordinary color neutral hadrons.", + "category": "nucl-ex" + }, + { + "text": "Tensor interaction constraints from beta decay recoil spin asymmetry of\n trapped atoms: We have measured the angular distribution of recoiling daughter nuclei\nemitted from the Gamow-Teller $\\beta$ decay of spin-polarized $^{80}$Rb. The\nasymmetry of this distribution vanishes to lowest order in the Standard Model\n(SM) in pure Gamow-Teller decays, producing an observable very sensitive to new\ninteractions. We measure the non-SM contribution to the asymmetry to be\n$A_{T}$= 0.015 $\\pm$ 0.029 (stat) $\\pm$ 0.019 (syst), consistent with the SM\nprediction. We constrain higher-order SM corrections using the measured\nmomentum dependence of the asymmetry, and their remaining uncertainty dominates\nthe systematic error. Future progress in determining the weak magnetism term\ntheoretically or experimentally would reduce the final errors. We describe the\nresulting constraints on fundamental 4-Fermi tensor interactions.", + "category": "nucl-ex" + }, + { + "text": "Proton-cluster femtoscopy with the HADES experiment: The matter created in Ag+Ag collisions at $\\sqrt{s_{NN}}$ = 2.55 GeV, as\nmeasured with the HADES experiment, can be characterized by similar\nthermodynamic quantities as Neutron Star Mergers, thus becoming an essential\nreference for the understanding of these compact stellar objects. One of the\nmethods applied to investigate heavy-ion collisions are femtoscopic\ncorrelations. They are a unique tool for the determination of the interactions\nbetween hadrons and allow to search for possible exited or unbound states of\nnuclear matter. We performed precise experimental studies of the correlations\nbetween protons and different clusters and compared them with the existing\ntheoretical descriptions.", + "category": "nucl-ex" + }, + { + "text": "Neutron Transfer Studied with a Radioactive beam of 24Ne, using TIARA at\n SPIRAL: A general experimental technique for high resolution studies of nucleon\ntransfer reactions using radioactive beams is briefly described, together with\nthe first new physics results that have been obtained with the new TIARA array.\nThese first results from TIARA are for the reaction 24Ne(d,p)25Ne, studied in\ninverse kinematics with a pure radioactive beam of 100,000 pps from the SPIRAL\nfacility at GANIL. The reaction probes the energies of neutron orbitals\nrelevant to very neutron rich nuclei in this mass region and the results\nhighlight the emergence of the N=16 magic number for neutrons and the\nassociated disappearance of the N=20 neutron magic number for the very neutron\nrich neon isotopes.", + "category": "nucl-ex" + }, + { + "text": "Cosmic ray measurements using the ISMRAN setup in a non-reactor\n environment: The cosmic rays data collected using a large area plastic scintillator array\nISMRAN (Indian Scintillator Matrix for Reactor AntiNeutrino) are presented. The\ndata collected serve as a useful benchmark of cosmogenic background in a\nnon-reactor environment for the future measurements of electron-antineutrinos\nto be performed using the ISMRAN setup. The zenith angle distribution of the\natmospheric muons has been measured and compared with Monte Carlo expectations.\nThe detector setup was further used to measure the lifetime distribution of\nstopped muons and extract their rates inside the detector matrix. The measured\nspectra of decaying muons and associated electrons show a good agreement with\nthe MC simulations performed through GEANT4 simulation.", + "category": "nucl-ex" + }, + { + "text": "A luminosity monitor for the A4 parity violation experiment at MAMI: A water Cherenkov luminosity monitor system with associated electronics has\nbeen developed for the A4 parity violation experiment at MAMI. The detector\nsystem measures the luminosity of the hydrogen target hit by the MAMI electron\nbeam and monitors the stability of the liquid hydrogen target. Both is required\nfor the precise study of the count rate asymmetries in the scattering of\nlongitudinally polarized electrons on unpolarized protons. Any helicity\ncorrelated fluctuation of the target density leads to false asymmetries. The\nperformance of the luminosity monitor, investigated in about 2000 hours with\nelectron beam, and the results of its application in the A4 experiment are\npresented.", + "category": "nucl-ex" + }, + { + "text": "Reply to Comment on \"High-Precision Determination of the Electric and\n Magnetic Form Factors of the Proton\": In arXiv:1108.3058v1 [nucl-ex], Arrington criticizes the Coulomb corrections\nwe applied in the analysis of high precision form factor data (see\nPhys.Rev.Lett.105:242001, 2010, arXiv:1007.5076v3 [nucl-ex]). We show, by\ncomparing different calculations cited in the Comment, that the criticism of\nthe Comment neglects the large uncertainty of \"more modern\" TPE corrections.\nThis uncertainty has also been seen in recent polarized measurements. We rerun\nour analysis using one of these calculations. The results show that the Comment\nexaggerates the quantitative effect at small Q^2.", + "category": "nucl-ex" + }, + { + "text": "Cross-sections for the ${^{27}\\!\\rm{Al}}(\u03b3,\\textit{x})^{24}\\rm{Na}$\n multiparticle reaction at $E_{\\rm{\u03b3max}}$ = 40 $\u00f7$ 95 MeV: The bremsstrahlung flux-averaged cross-sections $\\langle{\\sigma(E_{\\rm{\\gamma\nmax}})}\\rangle$ and the cross-sections per equivalent photon\n$\\langle{\\sigma(E_{\\rm{\\gamma max}})_{\\rm{Q}}}\\rangle$ were measured for the\nphotonuclear multiparticle reaction $^{27}\\!\\rm{Al}(\\gamma,\\textit{x};\n\\textit{x} = {^{3}\\rm{He}} + pd + 2pn)^{24}\\rm{Na}$ at bremsstrahlung end-point\nenergies ranging from 40 MeV to 95 MeV. The experiments were performed using\nthe beam from the NSC KIPT electron linear accelerator LUE-40 with the use of\nthe $\\gamma$-activation technique. The bremsstrahlung quantum flux was\ncalculated with the program GEANT4 and, in addition, was monitored by means of\nthe $^{100}\\rm{Mo}(\\gamma,n)^{99}\\rm{Mo}$ reaction. The cross-sections\n$\\sigma(E)$ were computed using the TALYS1.9 code with the default options. The\nmeasured average cross-sections $\\langle{\\sigma(E_{\\rm{\\gamma max}})}\\rangle$\nand $\\langle{\\sigma(E_{\\rm{\\gamma max}})_{\\rm{Q}}}\\rangle$ have appeared to be\nhigher by factors of 2.0 to 2.4 than the theoretical results. The experimental\nresults have been found to be in good agreement with the data of other\nlaboratories. Consideration is given to special features of calculation of\n$\\langle{\\sigma(E_{\\rm{\\gamma max}})}\\rangle$ and $\\langle{\\sigma(E_{\\rm{\\gamma\nmax}})_{\\rm{Q}}}\\rangle$ for the\n$^{27}\\!\\rm{Al}(\\gamma,\\textit{x})^{24}\\rm{Na}$ reaction, with occurrence of\nthree $^{27}\\!\\rm{Al}$ photodisintegration channels. The paper also discusses\nthe possibility of using the $^{27}\\!\\rm{Al}(\\gamma,\\textit{x})^{24}\\rm{Na}$\nreaction for monitoring the bremsstrahlung $\\gamma$-quantum flux in the photon\nenergy region above 30 MeV.", + "category": "nucl-ex" + }, + { + "text": "Scaling properties of the $\u0394\u03b3$ correlator and their\n implication for detection of the chiral magnetic effect in heavy-ion\n collisions: The scaling properties of the $\\Delta\\gamma$ correlator, inferred from the\nAnomalous Viscous Fluid Dynamics (AVFD) model, are used to investigate a\npossible chiral-magnetically-driven (CME) charge separation in $p$+Au, $d$+Au,\nRu+Ru, Zr+Zr, and Au+Au collisions at $\\sqrt s_{\\mathrm{NN}}=200$ GeV, and in\n$p$+Pb ($\\sqrt s_{\\mathrm{NN}}=5.02$ TeV) and Pb+Pb collisions at $\\sqrt\ns_{\\mathrm{NN}}=5.02$ and $2.76$ TeV. The results indicate that the values of\nthe quotient $\\Delta\\gamma/v_2$ with the elliptic flow coefficient $v_2$ for\n$p$+Au, $d$+Au, $p$+Pb, and Pb+Pb collisions, scale as $1/{\\rm N_{ch}}$\nconsistent with background-driven charge separation. By contrast, the\n$\\Delta\\gamma/v_2$ values for Ru+Ru, Zr+Zr, and Au+Au collisions show scaling\nviolations consistent with the presence of background plus a CME-driven\ncontribution. Quantifying this CME-driven component indicates that in\nmid-central collisions, the fraction of the measured $\\Delta\\gamma/v_2$\nattributable to the CME is approximately 27\\% for Au+Au and roughly a factor of\ntwo smaller for Ru+Ru and Zr+Zr, which show similar magnitudes.", + "category": "nucl-ex" + }, + { + "text": "Energy dependence of particle ratio fluctuations in central Pb+Pb\n collisions from $\\sqrt{s_{_{NN}}} =$~6.3 to 17.3 GeV: We present measurements of the energy dependence of event-by-event\nfluctuations in the K/pi and (p + \\bar{p})/pi multiplicity ratios in heavy ion\ncollisions at the CERN SPS. The particle ratio fluctuations were obtained for\ncentral Pb+Pb collisions at five collision energies, \\sqrt{s_{_{NN}}}, between\n6.3 and 17.3 GeV. After accounting for the effects of finite-number statistics\nand detector resolution, we extract the strength of non-statistical\nfluctuations at each energy. For the K/pi ratio, larger fluctuations than\nexpected for independent particle production are found at all collision\nenergies. The fluctuations in the (p + \\bar{p})/pi ratio are smaller than\nexpectations from independent particle production, indicating correlated pion\nand proton production from resonance decays. For both ratios, the deviation\nfrom purely statistical fluctuations shows an increase towards lower collision\nenergies. The results are compared to transport model calculations, which fail\nto describe the energy dependence of the K/pi ratio fluctuations.", + "category": "nucl-ex" + }, + { + "text": "Elliptic flow fluctuations in Au+Au collisions at $\\sqrt{s_{NN}}=200$\n GeV: Please note that after these results were reported at Quark Matter 2006 and\nposted on the preprint server it was found that what is reported here as\n\\textit{elliptic flow fluctuations}, should rather be taken as an upper limit\non the fluctuations. Further analysis has shown that fitting the multiplicity\ndependence of the q-distribution does not enable one to disentangle non-flow\nand fluctuations. The data from the q-vector distrubution does not, therefore,\nexclude the case of zero fluctuations. The remainder of these proceedings we\nleave as they were originally reported.", + "category": "nucl-ex" + }, + { + "text": "K$^-$ multi-nucleon absorption cross sections and branching ratios in\n $\u039b$p and $\u03a3^0$p final states: The determination of low-energy cross sections and branching ratios of the\nK$^-$ multi-nucleon absorption processes in $\\Lambda$p and $\\Sigma^0$p final\nstates performed by the AMADEUS collaboration is presented. Low momentum K$^-$\n($p_\\mathrm{K} \\simeq$ 127 MeV/c) produced at the DA$\\Phi$NE collider are\nimpinged on a Carbon target within the KLOE detector and the two and three\nnucleon absorption processes are disentangled by comparing the experimental\ndata to phenomenological calculations. The $\\Lambda$p spectra are interpreted\nin terms of K$^-$ multi-nucleon absorption processes; the possible contribution\nof a K$^-$pp bound state is demonstrated to overlap with the two nucleon\ncapture process, its absolute yield thus resulting indistinguishable.", + "category": "nucl-ex" + }, + { + "text": "Activation cross sections of deuteron induced reactions on niobium in\n the 30-50 MeV energy range: Activation cross-sections of deuterons induced reactions on Nb targets were\ndetermined with the aim of different applications and comparison with\ntheoretical models.", + "category": "nucl-ex" + }, + { + "text": "Momentum dependence of the phi-meson nuclear transparency: The production of phi mesons in proton collisions with C, Cu, Ag, and Au\ntargets has been studied via the phi -> K+K- decay at an incident beam energy\nof 2.83 GeV using the ANKE detector system at COSY. For the first time, the\nmomentum dependence of the nuclear transparency ratio, the in-medium phi width,\nand the differential cross section for phi meson production at forward angles\nhave been determined for these targets over the momentum range of 0.6 - 1.6\nGeV/c. There are indications of a significant momentum dependence in the value\nof the extracted phi width, which corresponds to an effective phi-N absorption\ncross section in the range of 14 - 21 mb.", + "category": "nucl-ex" + }, + { + "text": "Measurement of jet fragmentation in PbPb and pp collisions at\n sqrt(s[NN]) = 2.76 TeV: The jet fragmentation function of inclusive jets with transverse momentum pt\nabove 100 GeV in PbPb collisions has been measured using reconstructed charged\nparticles with pt above 1 GeV in a cone of radius 0.3 around the jet axis. A\ndata sample of PbPb collisions collected in 2011 at a nucleon-nucleon\ncenter-of-mass energy of sqrt(s[NN]) = 2.76 TeV corresponding to an integrated\nluminosity of 150 inverse microbarns is used. The results for PbPb collisions\nas a function of collision centrality and jet transverse momentum are compared\nto reference distributions based on pp data collected at the same\ncenter-of-mass energy in 2013, with an integrated luminosity of 5.3 inverse\npicobarns. A centrality-dependent modification of the fragmentation function is\nfound. For the most central collisions, a significant enhancement is observed\nin the PbPb / pp fragmentation function ratio for charged particles with pt\nless than 3 GeV. This enhancement is observed for all jet pt bins studied.", + "category": "nucl-ex" + }, + { + "text": "Fission involves a new state of nuclear matter: The rearrangement step of nuclear fission occurs within 0.17 yoctosecond, in\na new state of nuclear matter characterized by the formation of closed shells\nof nucleons. The determination of its lifetime is now based on the prompt\nneutron emission law. The width of isotopic distributions measures the\nuncertainty in the neutron number of the fragments. Magic mass numbers, 82 and\n126, play a major role in the mass distributions. Arguments are presented in\nfavour of an all-neutron state. The boson field responsible for the new\ncollective interaction has to be searched for.", + "category": "nucl-ex" + }, + { + "text": "Direct photon elliptic flow in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ =\n 2.76 TeV: The elliptic flow of inclusive and direct photons was measured at\nmid-rapidity in two centrality classes 0-20% and 20-40% in Pb-Pb collisions at\n$\\sqrt{s_{\\rm NN}}$ = 2.76 TeV by ALICE. Photons were detected with the highly\nsegmented electromagnetic calorimeter PHOS and via conversions in the detector\nmaterial with the $e^{+}e^{-}$ pairs reconstructed in the central tracking\nsystem. The results of the two methods were combined and the direct photon\nelliptic flow was extracted in the transverse momentum range $0.9 < p_{\\rm T} <\n6.2$ GeV/$c$. A comparison to RHIC data shows a similar magnitude of the\nmeasured direct-photon elliptic flow. Hydrodynamic and transport model\ncalculations are systematically lower than the data, but are found to be\ncompatible.", + "category": "nucl-ex" + }, + { + "text": "STAR results on medium properties and response of the medium to\n energetic partons: We report new STAR results on the consequences of highly energetic partons\npropagating through the medium formed in heavy ion collisions using\ncorrelations as an experimental probe. The recent results providing insights\nabout color factor effects and path length dependence of parton energy loss,\nsystem size dependence of di-hadron fragmentation functions, conical emission\nand ridge formation in heavy ion collisions are presented.", + "category": "nucl-ex" + }, + { + "text": "Schottky mass measurements of heavy neutron-rich nuclides in the element\n range $70\\leZ \\le79$ at the ESR: Storage-ring mass spectrometry was applied to neutron-rich $^{197}$Au\nprojectile fragments. Masses of $^{181,183}$Lu, $^{185,186}$Hf, $^{187,188}$Ta,\n$^{191}$W, and $^{192,193}$Re nuclei were measured for the first time. The\nuncertainty of previously known masses of $^{189,190}$W and $^{195}$Os nuclei\nwas improved. Observed irregularities on the smooth two-neutron separation\nenergies for Hf and W isotopes are linked to the collectivity phenomena in the\ncorresponding nuclei.", + "category": "nucl-ex" + }, + { + "text": "N=90 region: The decays of {152m,g}Eu to 152Sm: The decays of {152m,g}Eu to 152Sm have been studied by gamma-ray spectroscopy\nusing the 8pi Spectrometer, an array of 20 Compton-suppressed Ge detectors.\nVery weak gamma-decay branches in 152Sm were investigated through gamma-gamma\ncoincidence spectroscopy. All possible E2 transitions between states below 1550\nkeV with transition energies > 130 keV are observed, including the previously\nunobserved 2^+_3 to 0^+_2 401 keV transition. The results, combined with\nexisting lifetime data, provide a number of new or revised E2 transition\nstrengths which are critical for clarifying the collective structure of 152Sm\nand the N=90 isotones.", + "category": "nucl-ex" + }, + { + "text": "Shallow and diffuse spin-orbit potential for proton elastic scattering\n from neutron-rich helium isotopes at 71 MeV/nucleon: Vector analyzing powers for proton elastic scattering from 8He at 71\nMeV/nucleon have been measured using a solid polarized proton target operated\nin a low magnetic field of 0.1 T. The spin-orbit potential obtained from a\nphenomenological optical model analysis is found to be significantly shallower\nand more diffuse than the global systematics of stable nuclei, which is an\nindication that the spin-orbit potential is modified for scattering involving\nneutron-rich nuclei. A close similarity between the matter radius and the\nroot-mean-square radius of the spin-orbit potential is also identified.", + "category": "nucl-ex" + }, + { + "text": "Neutron occupancy of the 0d5/2 orbital and the N=16 shell closure in 24O: One-neutron knockout from 24O leading to the first excited state in 23O has\nbeen measured for a proton target at a beam energy of 62 MeV/nucleon. The decay\nenergy spectrum of the neutron unbound state of 23O was reconstructed from the\nmeasured four momenta of the 22O fragment and emitted neutron. A sharp peak was\nfound at Edecay=50$\\pm$3 keV, corresponding to an excited state in 23O at\n2.78$\\pm$0.11 MeV, as observed in previous measurements. The longitudinal\nmomentum distribution for this state was consistent with d -wave neutron\nknockout, providing support for a J{\\pi} assignment of 5/2+. The associated\nspectroscopic factor was deduced to be C2S(0d5/2)=4.1$\\pm$0.4 by comparing the\nmeasured cross section (View the MathML source) with a distorted wave impulse\napproximation calculation. Such a large occupancy for the neutron 0d5/2 orbital\nis in line with the N=16 shell closure in 24O.", + "category": "nucl-ex" + }, + { + "text": "Experiments for the absolute neutrino mass measurement: Experimental results and perspectives of different methods to measure the\nabsolute mass scale of neutrinos are briefly reviewed. The mass sensitivities\nfrom cosmological observations, double beta decay searches and single beta\ndecay spectroscopy differ in sensitivity and model dependance. Next generation\nexperiments in the three fields reach the sensitivity for the lightest mass\neigenstate of $m_1<0.2eV$, which will finally answer the question if neutrino\nmass eigenstates are degenerate. This sensitivity is also reached by the only\nmodel-independent approach of single beta decay (KATRIN experiment). For higher\nsensitivities on cost of model-dependance the neutrinoless double beta decay\nsearch and cosmological observation have to be applied. Here, in the next\ndecade sensitivities are approached with the potential to test inverted\nhierarchy models.", + "category": "nucl-ex" + }, + { + "text": "ALICE results on quarkonium production in pp, p-Pb and Pb-Pb collisions: The study of quarkonia, bound states of heavy (charm or bottom)\nquark-antiquark pairs such as the J/psi or the Upsilon?, provides insight into\nthe earliest and hottest stages of high-energy nucleus-nucleus collisions where\nthe formation of a Quark-Gluon Plasma is expected. High-precision data from\nproton-proton collisions represent an essential baseline for the measurement of\nnuclear modifications in nucleus-nucleus collisions and serve also as a crucial\ntest for models of quarkonium hadroproduction. Another fundamental tool to\nunderstand the quarkonium production in nucleus-nucleus collisions is the the\nstudy of proton-nucleus interactions, which allows one to investigate cold\nnuclear matter effects, such as parton shadowing or gluon saturation. The ALICE\ndetector provides excellent capabilities to study quarkonium production at the\nLarge Hadron Collider at both central and forward rapidity. An overview on\nALICE results on quarkonium production in pp, p-Pb and Pb-Pb collisions is\npresented. Results are compared to theoretical model predictions.", + "category": "nucl-ex" + }, + { + "text": "Reexamining the half-lives of 195Os and 195Ir: Currently the half-life of 195Os is listed as unknown in most databases\nbecause the value of the only available measurement had been reassigned. We\nargue that the original assignment is correct and re-evaluate the half-life of\n195Os to be 6.5(11)min, consistent with the original measurement. We also\nsuggest to reassign the half-life of 195Ir to 2.29(17)h.", + "category": "nucl-ex" + }, + { + "text": "Completing the nuclear reaction puzzle of the nucleosynthesis of 92Mo: One of the greatest questions for modern physics to address is how elements\nheavier than iron are created in extreme, astrophysical environments. A\nparticularly challenging part of that question is the creation of the so-called\np-nuclei, which are believed to be mainly produced in some types of supernovae.\nThe lack of needed nuclear data presents an obstacle in nailing down the\nprecise site and astrophysical conditions. In this work, we present for the\nfirst time measurements on the nuclear level density and average strength\nfunction of $^{92}$Mo. State-of-the-art p-process calculations systematically\nunderestimate the observed solar abundance of this isotope. Our data provide\nstringent constraints on the $^{91}$Nb$(p,{\\gamma})^{92}$Mo reaction rate,\nwhich is the last unmeasured reaction in the nucleosynthesis puzzle of\n$^{92}$Mo. Based on our results, we conclude that the $^{92}$Mo abundance\nanomaly is not due to the nuclear physics input to astrophysical model\ncalculations.", + "category": "nucl-ex" + }, + { + "text": "Electromagnetic Dissociation of 8B and the Rate of the 7Be(p,gamma)8B\n Reaction in the Sun: In an effort to better determine the 7Be(p,gamma)8B reaction rate, we have\nperformed inclusive and exclusive measurements of the Coulomb dissociation of\n8B. The former was a study of longitudinal momentum distributions of 7Be\nfragments emitted in the Coulomb breakup of intermediate energy 8B beams on Pb\nand Ag targets. Analysis of these data yielded the E2 contribution to the\nbreakup cross section. In the exclusive measurement, we determined the cross\nsection for the Coulomb breakup of 8B on Pb at low relative energies in order\nto infer the astrophysical S factor for the 7Be(p,gamma)8B reaction.\nInterpreting the measurements with 1st-order perturbation theory, we obtained\nSE2/SE1 = 4.7 (+ 2.0,- 1.3) times 10^-4 at Erel = 0.6 MeV, and S17(0) = 17.8 (+\n1.4,- 1.2) eV b. Semiclassical 1st-order perturbation theory and fully quantum\nmechanical continuum-discretized coupled channels analyses yield nearly\nidentical results for the E1 strength relevant to solar neutrino flux\ncalculations, suggesting that theoretical reaction mechanism uncertainties need\nnot limit the precision of Coulomb breakup determinations of the 7Be(p,gamma)8B\nS factor. A recommended value of S17(0) based on a weighted average of this and\nother measurements is presented.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the Vector and Tensor Asymmetries at Large Missing\n Momentum in Quasielastic $(\\vec{e}, e^{\\prime}p)$ Electron Scattering from\n Deuterium: We report the measurement of the beam-vector and tensor asymmetries\n$A^V_{ed}$ and $A^T_d$ in quasielastic $(\\vec{e}, e^{\\prime}p)$\nelectrodisintegration of the deuteron at the MIT-Bates Linear Accelerator\nCenter up to missing momentum of 500~MeV/c. Data were collected simultaneously\nover a momentum transfer range $0.1< Q^2<0.5$~(GeV/c)$^2$ with the Bates Large\nAcceptance Spectrometer Toroid using an internal deuterium gas target,\npolarized sequentially in both vector and tensor states. The data are compared\nwith calculations. The beam-vector asymmetry $A^V_{ed}$ is found to be directly\nsensitive to the $D$-wave component of the deuteron and have a zero-crossing at\na missing momentum of about 320~MeV/c, as predicted. The tensor asymmetry\n$A^T_d$ at large missing momentum is found to be dominated by the influence of\nthe tensor force in the neutron-proton final-state interaction. The new data\nprovide a strong constraint on theoretical models.", + "category": "nucl-ex" + }, + { + "text": "Production cross section and decay study of $^{243}$Es and $^{249}$Md: In the study of the odd-$Z$, even-$N$ nuclei $^{243}$Es and $^{249}$Md,\nperformed at the University of Jyv\\\"askyl\\\"a, the fusion-evaporation reactions\n$^{197}$Au($^{48}$Ca,2$n$)$^{243}$Es and $^{203}$Tl($^{48}$Ca,2$n$)$^{249}$Md\nhave been used for the first time. Fusion-evaporation residues were selected\nand detected using the RITU gas-filled separator coupled with the focal-plane\nspectrometer GREAT. For $^{243}$Es, the recoil decay correlation analysis\nyielded a half-life of $24 \\pm 3$s, and a maximum production cross section of\n$37 \\pm 10$ nb. In the same way, a half-life of $26 \\pm 1$ s, an $\\alpha$\nbranching ratio of 75 $\\pm$ 5%, and a maximum production cross section of 300\n$\\pm$ 80 nb were determined for $^{249}$Md. The decay properties of $^{245}$Es,\nthe daughter of $^{249}$Md, were also measured: an $\\alpha$ branching ratio of\n54 $\\pm$ 7% and a half-life of 65 $\\pm$ 6 s. Experimental cross sections were\ncompared to the results of calculations performed using the KEWPIE2 statistical\nfusion-evaporation code.", + "category": "nucl-ex" + }, + { + "text": "Beam energy dependent two-pion interferometry and the freeze-out\n eccentricity of pions in heavy ion collisions at STAR: We present results of analyses of two-pion interferometry in Au+Au collisions\nat $\\sqrt{s_{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200 GeV measured in the\nSTAR detector as part of the RHIC Beam Energy Scan program. The extracted\ncorrelation lengths (HBT radii) are studied as a function of beam energy,\nazimuthal angle relative to the reaction plane, centrality, and transverse mass\n($m_{T}$) of the particles. The azimuthal analysis allows extraction of the\neccentricity of the entire fireball at kinetic freeze-out. The energy\ndependence of this observable is expected to be sensitive to changes in the\nequation of state. A new global fit method is studied as an alternate method to\ndirectly measure the parameters in the azimuthal analysis. The eccentricity\nshows a monotonic decrease with beam energy that is qualitatively consistent\nwith the trend from all model predictions and quantitatively consistent with a\nhadronic transport model.", + "category": "nucl-ex" + }, + { + "text": "Hypernuclear spectroscopy with K$^-$ at rest on $^7$Li, $^9$Be, $^{13}$C\n and $^{16}$O: The FINUDA experiment collected data to study the production of hypernuclei\non different nuclear targets. The hypernucleus formation occurred through the\nstrangeness-exchange reaction $K^-_{stop} + \\; ^AZ \\rightarrow \\; ^A_{\\Lambda}Z\n+ \\pi^-$. From the analysis of the momentum of the emerging $\\pi^-$, binding\nenergies and formation probabilities of $^7_{\\Lambda}$Li, $^9_{\\Lambda}$Be,\n$^{13}_{\\Lambda}$C and $^{16}_{\\Lambda}$O have been measured and are here\npresented. The behavior of the formation probability as a function of the\natomic mass number A is also discussed.", + "category": "nucl-ex" + }, + { + "text": "Studying the QGP with Jets at the LHC and RHIC: We review the current status of jet measurements in heavy-ion collisions at\nthe Large Hadron Collider (LHC) and the Relativistic Heavy Ion Collider (RHIC).\nWe discuss how the current measurements provide information about the\nquark-gluon plasma and discuss near future opportunities at both RHIC and the\nLHC.", + "category": "nucl-ex" + }, + { + "text": "Anomaly in the K^0_S Sigma^+ photoproduction cross section off the\n proton at the K* threshold: The $\\gamma + p \\rightarrow K^0 + \\Sigma^+$ photoproduction reaction is\ninvestigated in the energy region from threshold to $E_\\gamma = 2250$\\,MeV. The\ndifferential cross section exhibits increasing forward-peaking with energy, but\nonly up to the $K^*$ threshold. Beyond, it suddenly returns to a flat\ndistribution with the forward cross section dropping by a factor of four. In\nthe total cross section a pronounced structure is observed between the\n$K^*\\Lambda$ and $K^*\\Sigma$ thresholds. It is speculated whether this signals\nthe turnover of the reaction mechanism from t-channel exchange below the $K^*$\nproduction threshold to an s-channel mechanism associated with the formation of\na dynamically generated $K^*$-hyperon intermediate state.", + "category": "nucl-ex" + }, + { + "text": "Fragmentation of relativistic nuclei in peripheral interactions in\n nuclear track emulsion: The technique of nuclear track emulsions is used to explore the fragmentation\nof light relativistic nuclei down to the most peripheral interactions - nuclear\n\"white\" stars. A complete pattern of therelativistic dissociation of a $^8$B\nnucleus with target fragment accompaniment is presented. Relativistic\ndissociation $^{9}$Be$\\to2\\alpha$ is explored using significant statistics and\na relative contribution of $^{8}$Be decays from 0$^+$ and 2$^+$ states is\nestablished. Target fragment accompaniments are shown for relativistic\nfragmentation $^{14}$N$\\to$3He+H and $^{22}$Ne$\\to$5He. The leading role of the\nelectromagnetic dissociation on heavy nuclei with respect to break-ups on\ntarget protons is demonstrated in all these cases. It is possible to conclude\nthat the peripheral dissociation of relativistic nuclei in nuclear track\nemulsion is a unique tool to study many-body systems composed of lightest\nnuclei and nucleons in the energy scale relevant for nuclear astrophysics.", + "category": "nucl-ex" + }, + { + "text": "First Measurement of $\u039e^-$ Polarization in Photoproduction: Despite decades of studies of the photoproduction of hyperons, both their\nproduction mechanisms and their spectra of excited states are still largely\nunknown. While the parity-violating weak decay of hyperons offers a means of\nmeasuring their polarization, which could help discern their production\nmechanisms and identify their excitation spectra, no such study has been\npossible for doubly strange baryons in photoproduction, due to low production\ncross sections. However, by making use of the reaction $\\gamma p \\to K^+ K^+\n\\Xi^-$, we have measured, for the first time, the induced polarization, $P$,\nand the transferred polarization from circularly polarized real photons,\ncharacterized by $C_x$ and $C_z$, to recoiling $\\Xi^-$s. The data were obtained\nusing the CEBAF Large Acceptance Spectrometer (CLAS) at Jefferson Lab for\nphoton energies from just over threshold (2.4 GeV) to 5.45 GeV. These\nfirst-time measurements are compared, and are shown to broadly agree, with\nmodel predictions in which cascade photoproduction proceeds through the decay\nof intermediate hyperon resonances that are produced via relativistic meson\nexchange, offering a new step forward in the understanding of the production\nand polarization of doubly-strange baryons.", + "category": "nucl-ex" + }, + { + "text": "The 16N Calibration Source for the Sudbury Neutrino Observatory: A calibration source using gamma-rays from 16N (t_1/2 = 7.13 s) beta-decay\nhas been developed for the Sudbury Neutrino Observatory (SNO) for the purpose\nof energy and other calibrations. The 16N is produced via the (n,p) reaction on\n16O in the form of CO2 gas using 14-MeV neutrons from a commercially available\nDeuterium-Tritium (DT) generator. The 16N is produced in a shielding pit in a\nutility room near the SNO cavity and transferred to the water volumes (D2O or\nH2O) in a CO2 gas stream via small diameter capillary tubing. The bulk of the\nactivity decays in a decay/trigger chamber designed to block the energetic\nbeta-particles yet permit the primary branch 6.13 MeV gamma-rays to exit.\nDetection of the coincident beta-particles with plastic scintillator lining the\nwalls of the decay chamber volume provides a tag for the SNO electronics. This\npaper gives details of the production, transfer, and triggering systems for\nthis source along with a discussion of the source gamma-ray output and\nperformance.", + "category": "nucl-ex" + }, + { + "text": "J/$\u03c8$ suppression in In-In collisions at 158 GeV/nucleon: The NA60 experiment has studied J/$\\psi$ production in Indium-Indium\ncollisions at 158 A$\\cdot$GeV. In this paper we present an updated set of\nresults obtained with the complete set of available statistics and an improved\nalignment of the vertex tracker. The centrality dependence of the J/$\\psi$\nproduction, obtained with an analysis technique based only on the J/$\\psi$\nsample, indicates that a suppression beyond that induced by nuclear absorption\nis present in In-In collisions, setting in at $\\sim$80 participant nucleons. A\nfirst study of the systematic errors related with this measurement is\ndiscussed. We also present preliminary results on the J/$\\psi$ azimuthal\ndistributions.", + "category": "nucl-ex" + }, + { + "text": "Experimental activities in few-body physics: Understanding the few-nucleon system remains one of the challenges in modern\nnuclear and hadron physics. Observables in few-nucleon scattering processes are\nsensitive probes to study the two and many-body interactions between nucleons\nin nuclei. In the past decades, several facilities provided a large data base\nto study in detail the three-nucleon interactions below the pion-production\nthreshold by exploiting polarized proton and deuteron beams and\nlarge-acceptance detectors. Only since recently, the four-nucleon scattering\nprocess at intermediate energies has been explored. In addition, there is a\nfocus to collect data in the hyperon-nucleon sector, thereby providing access\nto understand the more general baryon-baryon interaction. In this contribution,\nsome recent results in the few-nucleon sector are discussed together with some\nof the preliminary results from a pioneering and exclusive study of the\nfour-nucleon scattering process. Furthermore, this paper discusses the\nexperimental activities in the hyperon sector, in particular, the perspectives\nof the hyperon program of PANDA.", + "category": "nucl-ex" + }, + { + "text": "Tensor Ayy and vector Ay analyzing powers in the H(d,d')X and\n ^{12}C(d,d')X reactons at initial deuteron momenta of 9 GeV/c in the region\n of baryonic resonances excitation: The angular dependence of the tensor Ayy and vector Ay analyzing powers in\nthe inelastic scattering of deuterons with a momentum of 9.0 GeV/c on hydrogen\nand carbon have been measured. The range of measurements corresponds to the\nbaryonic resonance excitation with masses 2.2--2.6 GeV/c^2. The Ayy data being\nin good agreement with the previous results demonstrate an approximate $t$\nscaling up to -1.5 (GeV/c)^2. The large values of A_y show a significant role\nof the spin-dependent part of the elementary amplitude of the NN->NN* reaction.\nThe results of the experiment are compared with model predictions of the\nplane-wave impulse approximation.", + "category": "nucl-ex" + }, + { + "text": "Method for High Accuracy Multiplicity Correlation Measurements: Multiplicity correlation measurements provide insight into the dynamics of\nhigh energy collisions. Models describing these collisions need these\ncorrelation measurements to tune the strengths of the underlying QCD processes\nwhich influence all observables. Detectors, however, often possess limited\ncoverage or reduced efficiency that influence correlation measurements in\nobscure ways. In this paper, the effects of non-uniform detection acceptance\nand efficiency on the measurement of multiplicity correlations between two\ndistinct detector regions (termed forward-backward correlations) are derived.\nAn analysis method with such effects built-in is developed and subsequently\nverified using different event generators. The resulting method accounts for\nacceptance and efficiency in a model independent manner with high accuracy\nthereby shedding light on the relative contributions of the underlying\nprocesses to particle production.", + "category": "nucl-ex" + }, + { + "text": "The beta-Oslo method: experimentally constrained ($n,\u03b3$) reaction\n rates relevant to the $r$-process: Unknown neutron-capture reaction rates remain a significant source of\nuncertainty in state-of-the-art $r$-process nucleosynthesis reaction network\ncalculations. As the $r$-process involves highly neutron-rich nuclei for which\ndirect ($n,\\gamma$) cross-section measurements are virtually impossible,\nindirect methods are called for to constrain ($n,\\gamma$) cross sections used\nas input for the $r$-process nuclear network. Here we discuss the newly\ndeveloped beta-Oslo method, which is capable of providing experimental input\nfor calculating ($n,\\gamma$) rates of neutron-rich nuclei. The beta-Oslo method\nrepresents a first step towards constraining neutron-capture rates of\nimportance to the $r$-process.", + "category": "nucl-ex" + }, + { + "text": "Systematic comparison of ISOLDE-SC yields with calculated in-target\n production rates: Recently, a series of dedicated inverse-kinematics experiments performed at\nGSI, Darmstadt, has brought an important progress in our understanding of\nproton and heavy-ion induced reactions at relativistic energies. The nuclear\nreaction code ABRABLA that has been developed and benchmarked against the\nresults of these experiments has been used to calculate nuclide production\ncross sections at different energies and with different targets and beams.\nThese calculations are used to estimate nuclide production rates by protons in\nthick targets, taking into account the energy loss and the attenuation of the\nproton beam in the target, as well as the low-energy fission induced by the\nsecondary neutrons. The results are compared to the yields of isotopes of\nvarious elements obtained from different targets at CERN-ISOLDE with 600 MeV\nprotons, and the overall extraction efficiencies are deduced. The dependence of\nthese extraction efficiencies on the nuclide half-life is found to follow a\nsimple pattern in many different cases. A simple function is proposed to\nparameterize this behavior in a way that quantifies the essential properties of\nthe extraction efficiency for the element and the target - ion-source system in\nquestion.", + "category": "nucl-ex" + }, + { + "text": "Production of $^{4}$He and $^{4}\\overline{\\textrm{He}}$ in Pb-Pb\n collisions at $\\sqrt{s_{\\mathrm{NN}}}$ = 2.76 TeV at the LHC: Results on the production of $^{4}{\\textrm{He}}$ and\n$^{4}\\overline{\\textrm{He}}$ nuclei in Pb-Pb collisions at $\n\\sqrt{s_{\\mathrm{NN}}} = 2.76 $ TeV in the rapidity range $ \\mid y \\mid < 1$,\nusing the ALICE detector, are presented in this paper. The rapidity densities\ncorresponding to 0-10% central events are found to be $\\mathrm{d}N/\\mathrm{d}y\n_{^{4}\\mathrm{He}} = (0.8 \\pm 0.4 ~(\\mathrm{stat}) \\pm\n0.3~(\\mathrm{syst}))\\times 10^{-6}$ and $\\mathrm{d}N/\\mathrm{d}y\n_{^{4}\\mathrm{\\overline{He}}} = (1.1 \\pm 0.4~(\\mathrm{stat}) \\pm\n0.2~(\\mathrm{syst}))\\times 10^{-6}$, respectively. This is in agreement with\nthe statistical thermal model expectation assuming the same chemical freeze-out\ntemperature ($T_{\\mathrm{chem}}$ = 156 MeV) as for light hadrons. The measured\nratio of $^{4}\\overline{\\mathrm{He}}$/$^{4}\\mathrm{He}$ is $1.4 \\pm\n0.8~(\\mathrm{stat}) \\pm 0.5~(\\mathrm{syst})$.", + "category": "nucl-ex" + }, + { + "text": "The nucleon resonance structure from exclusive $\u03c0^+\u03c0^-p$\n photo-/electroproduction off protons: The results on the photo- and electroexcitation amplitudes of most nucleon\nresonances in the mass range up to 2.0 GeV determined from the CLAS\nexperimental data on exclusive $\\pi^+\\pi^-p$ photo-/electroproduction off\nprotons in collaboration between the Jefferson Lab and Moscow State University\nare presented. The first and only available results on electroexcitation\namplitudes from CLAS in a wide range of photon virtualities $Q^2$ $<$ 5.0\nGeV$^2$ revealed the nucleon resonance structure as a complex interplay between\nthe inner core of three dressed quarks and external meson-baryon cloud. These\nresults shed light on the strong QCD dynamics which underlines the generation\nof excited nucleon states of different structural features from confined quarks\nand gluons. The future prospects of these studies in the new era of experiments\nwith the CLAS12 detector, which started successfully in Spring of 2018, are\noutlined.", + "category": "nucl-ex" + }, + { + "text": "Review of Forward Physics at RHIC: The RHIC high energy collision of species ranging from p+p, p(d)+A to A+A\nprovide access to the {small-x} component of the hadron wave function. The RHIC\nprogram has brought renewed interest in that subject with its ability to reach\nvalues of the parton momentum fraction smaller than 0.01 with studies of\nparticle production at high rapidity. Furthermore, the use of heavy nuclei in\nthe p(d)+A collisions facilitates the study of saturation effects in the\ngluonic component of the nuclei because the appropriate scale for that regime\ngrows as A^1/3. We review the experimental results of the RHIC program that\nhave relevance to {small-x} emphasizing the physics extracted from d+Au\ncollisions and their comparison to p+p collisions at the same energy.", + "category": "nucl-ex" + }, + { + "text": "Hadron yields and the phase diagram of strongly interacting matter: This paper presents a brief review of the interpretation of measurements of\nhadron yields in hadronic interactions within the framework of thermal models,\nover a broad energy range (from SIS to LHC energies, $\\sqrt{s_{NN}} \\simeq$ 2.5\nGeV -- 5 TeV). Recent experimental results and theoretical developments are\nreported, with an emphasis on topics discussed during the Quark Matter 2014\nconference.", + "category": "nucl-ex" + }, + { + "text": "Anti-flow of K$^0_s$ Mesons in 6 AGeV Au + Au Collisions: We have measured the sideward flow of neutral strange ($K^0_s$) mesons in 6\nAGeV Au + Au collisions. A prominent anti-flow signal is observed for an impact\nparameter range (b $\\lesssim 7$ fm) which spans central and mid-central events.\nSince the $K^0_s$ scattering cross section is relatively small in nuclear\nmatter, this observation suggests that the in-medium kaon vector potential\nplays an important role in high density nuclear matter.", + "category": "nucl-ex" + }, + { + "text": "Search for the Chiral Magnetic Effect in Relativistic Heavy-Ion\n Collisions: Relativistic heavy-ion collisions provide an ideal environment to study the\nemergent phenomena in quantum chromodynamics (QCD). The chiral magnetic effect\n(CME) is one of the most interesting, arising from the topological charge\nfluctuations of QCD vacua, immersed in a strong magnetic field. Since the first\nmeasurement nearly a decade ago of the possibly CME-induced charge correlation,\nextensive studies have been devoted to background contributions to those\nmeasurements. Many new ideas and techniques have been developed to reduce or\neliminate the backgrounds. This article reviews these developments and the\noverall progress in the search for the CME.", + "category": "nucl-ex" + }, + { + "text": "Comment on \"Evidence for narrow resonant structures at $W\\approx$ 1.68\n GeV and $W\\approx$ 1.72 GeV in real Compton scattering off the proton\": We comment on the statement by Kuznetsov et al. that the structure around\nW=1.72 GeV seen in the beam asymmetry in Compton scattering off the proton is\nnot observed in the total cross section of $\\eta$ photoproduction on the\nneutron.", + "category": "nucl-ex" + }, + { + "text": "Energy Deconvolution of Cross Section Measurements with an Application\n to the 12C(\u03b1,\u03b3)16O Reaction: A general framework for deconvoluting the effects of energy averaging on\ncharged-particle reaction measurements is presented. There are many potentially\ncorrect approaches to the problem; the relative merits of some of are\ndiscussed. These deconvolution methods are applied to recent\n12C(\\alpha,\\gamma)16O measurements.", + "category": "nucl-ex" + }, + { + "text": "Exclusive proton asymmetry measurement in non-mesonic weak decay of\n polarized 5_Lambda_He: The asymmetry parameter alpha_p^NM for a proton exclusively emitted in the\nLambda p -> np process was, for the first time, measured in the non-mesonic\nweak decay of a polarized 5_La,bda_He hypernucleus by selecting the\nproton-neutron pairs emitted in the back-to-back kinematics. The highly\npolarized 5_Lambda_He was abundantly produced with the (pi+,K+) reaction at\n1.05GeV/c in the scattering angular range of +-15$ degrees. The obtained value\nalpha_p^NM=0.31+-0.22, as well as that for inclusive protons,\nalpha_p^NM=0.11+-0.08+-0.04, largely contradicts recent theoretical values of\naround -0.6, although these calculations well reproduce the branching ratios of\nnon-mesonic weak decay.", + "category": "nucl-ex" + }, + { + "text": "The neutron-gamma Feynman variance to mean approach: gamma detection and\n total neutron-gamma detection (theory and practice): Two versions of the neutron-gamma variance to mean (Feynman-alpha method or\nFeynman-Y function) formula for either gamma detection only or total\nneutron-gamma detection, respectively, are derived and compared in this paper.\nThe new formulas have a particular importance for detectors of either gamma\nphotons or detectors sensitive to both neutron and gamma radiation. If applied\nto a plastic or liquid scintillation detector, the total neutron-gamma\ndetection Feynman-Y expression corresponds to a situation where no\ndiscrimination is made between neutrons and gamma particles. The gamma variance\nto mean formulas are useful when a detector of only gamma radiation is used or\nwhen working with a combined neutron-gamma detector at high count rates. The\ntheoretical derivation is based on the Chapman-Kolmogorov equation with\ninclusion of general reactions and passage intensities for neutrons and gammas,\nbut with the inclusion of prompt reactions only. A one energy group\napproximation is considered. The comparison of the two different theories is\nmade by using reaction intensities obtained in MCNPX simulations with a\nsimplified geometry for two scintillation detectors and a 252Cf-source enclosed\nin a steel container. In addition, the variance to mean ratios, neutron, gamma\nand total neutron-gamma, are evaluated experimentally for a weak 252Cf\nneutron-gamma source in a steel container, a 137Cs random gamma source and a\n22Na correlated gamma source. Due to the focus being on the possibility of\nusing neutron-gamma variance to mean theories for both reactor and safeguards\napplications, we limited the present study to the general analytical\nexpressions for Feynman-Y formulas.", + "category": "nucl-ex" + }, + { + "text": "Characterisation of radiation damage in silicon photomultipliers with a\n Monte Carlo model: Measured response functions and low photon yield spectra of silicon\nphotomultipliers (SiPM) were compared to multi-photoelectron pulse-height\ndistributions generated by a Monte Carlo model. Characteristic parameters for\nSiPM were derived. The devices were irradiated with 14 MeV electrons at the\nMainz microtron MAMI. It is shown that the first noticeable damage consists of\nan increase in the rate of dark pulses and the loss of uniformity in the pixel\ngains. Higher radiation doses reduced also the photon detection efficiency. The\nresults are especially relevant for applications of SiPM in fibre detectors at\nhigh luminosity experiments.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the branching ratio for beta-delayed alpha decay of 16N: While the 12C(a,g)16O reaction plays a central role in nuclear astrophysics,\nthe cross section at energies relevant to hydrostatic helium burning is too\nsmall to be directly measured in the laboratory. The beta-delayed alpha\nspectrum of 16N can be used to constrain the extrapolation of the E1 component\nof the S-factor; however, with this approach the resulting S-factor becomes\nstrongly correlated with the assumed beta-alpha branching ratio. We have\nremeasured the beta-alpha branching ratio by implanting 16N ions in a segmented\nSi detector and counting the number of beta-alpha decays relative to the number\nof implantations. Our result, 1.49(5)e-5, represents a 24% increase compared to\nthe accepted value and implies an increase of 14% in the extrapolated S-factor.", + "category": "nucl-ex" + }, + { + "text": "The QCD Phase Diagram: Expectations and Challenges: A survey is given of recent QCD theory advances concerning the phase diagram,\nin particular the indications for a critical point and adjacent first order\nphase transition at high baryo-chemical potential, and the new ideas concerning\na further phase at high $\\mu_{B}$, the quarkyonic matter phase. The latter\nstate might finally explain the hadro-chemical equilibrium freeze-out points\nfrom A+A collisions at energies below SPS energy. We review several\nevent-by-event fluctuation signals that promise to shed a light on the\nexistence of a critical point, and we discuss its possible reflection in recent\nlattice QCD calculations.", + "category": "nucl-ex" + }, + { + "text": "Measurement of cold nuclear matter effects for inclusive $J/\u03c8$ in\n $p$+Au collisions at $\\sqrt{s_{_{\\mathrm{NN}}}}$ = 200 GeV: Measurement by the STAR experiment at RHIC of the cold nuclear matter (CNM)\neffects experienced by inclusive $J/\\psi$ at mid-rapidity in 0-100\\% $p$+Au\ncollisions at $\\sqrt{s_{_{\\mathrm{NN}}}}$ = 200 GeV is presented. Such effects\nare quantified utilizing the nuclear modification factor, $R_{p\\mathrm{Au}}$,\nobtained by taking a ratio of $J/\\psi$ yield in $p$+Au collisions to that in\n$p$+$p$ collisions scaled by the number of binary nucleon-nucleon collisions.\nThe differential $J/\\psi$ yield in both $p$+$p$ and $p$+Au collisions is\nmeasured through the dimuon decay channel, taking advantage of the trigger\ncapability provided by the Muon Telescope Detector in the RHIC 2015 run.\nConsequently, the $J/\\psi$ $R_{p\\mathrm{Au}}$ is derived within the transverse\nmomentum ($p_{\\mathrm{T}}$) range of 0 to 10 GeV/$c$. A suppression of\napproximately 30% is observed for $p_{\\mathrm{T}}<2$ GeV/$c$, while $J/\\psi$\n$R_{p\\mathrm{Au}}$ becomes compatible with unity for $p_{\\mathrm{T}}$ greater\nthan 3 GeV/$c$, indicating the $J/\\psi$ yield is minimally affected by the CNM\neffects at high $p_{\\mathrm{T}}$. Comparison to a similar measurement from\n0-20% central Au+Au collisions reveals that the observed strong $J/\\psi$\nsuppression above 3 Gev/$c$ is mostly due to the hot medium effects, providing\nstrong evidence for the formation of the quark-gluon plasma in these\ncollisions. Several model calculations show qualitative agreement with the\nmeasured $J/\\psi$ $R_{p\\mathrm{Au}}$, while their agreement with the $J/\\psi$\nyields in $p$+$p$ and $p$+Au collisions is worse.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the radiative neutron capture cross section of 206Pb and\n its astrophysical implications: The (n, gamma) cross section of 206Pb has been measured at the CERN n_TOF\nfacility with high resolution in the energy range from 1 eV to 600 keV by using\ntwo optimized C6D6 detectors. In the investigated energy interval about 130\nresonances could be observed, from which 61 had enough statistics to be\nreliably analyzed via the R-matrix analysis code SAMMY. Experimental\nuncertainties were minimized, in particular with respect to (i) angular\ndistribution effects of the prompt capture gamma-rays, and to (ii) the\nTOF-dependent background due to sample-scattered neutrons. Other background\ncomponents were addressed by background measurements with an enriched 208Pb\nsample. The effect of the lower energy cutoff in the pulse height spectra of\nthe C6D6 detectors was carefully corrected via Monte Carlo simulations.\nCompared to previous 206Pb values, the Maxwellian averaged capture cross\nsections derived from these data are about 20% and 9% lower at thermal energies\nof 5 keV and 30 keV, respectively. These new results have a direct impact on\nthe s-process abundance of 206Pb, which represents an important test for the\ninterpretation of the cosmic clock based on the decay of 238U.", + "category": "nucl-ex" + }, + { + "text": "Photoproduction of pi0-mesons off neutrons in the nucleon resonance\n region: Precise angular distributions have been measured for the first time for the\nphotoproduction of $\\pi^{0}$-mesons off neutrons bound in the deuteron. The\neffects from nuclear Fermi motion have been eliminated by a complete kinematic\nreconstruction of the final state. The influence of final-state-interaction\neffects has been estimated by a comparison of the reaction cross section for\nquasi-free protons bound in the deuteron to the results for free protons and\nthen applied as a correction to the quasi-free neutron data. The experiment was\nperformed at the tagged photon facility of the Mainz Microtron MAMI with the\nCrystal Ball and TAPS detector setup for incident photon energies between\n$0.45$~GeV and $1.4$~GeV. The results are compared to the predictions from\nreaction models and partial-wave analyses based on data from other isospin\nchannels. The model predictions show large discrepancies among each other and\nthe present data will provide much tighter constraints. This is demonstrated by\nthe results of a new analysis in the framework of the Bonn-Gatchina\ncoupled-channel analysis which included the present data.", + "category": "nucl-ex" + }, + { + "text": "Coulomb displacement energies as a probe for nucleon pairing in the\n $f_{7/2}$ shell: Coulomb displacement energies of $T=1/2$ mirror nuclei have been studied via\na series of high-precision $Q_\\mathrm{EC}$-value measurements with the double\nPenning trap mass spectrometer JYFLTRAP. Most recently, the $Q_\\mathrm{EC}$\nvalues of the $f_{7/2}$-shell mirror nuclei $^{45}$V\n($Q_\\mathrm{EC}=7123.82(22)$ keV) and $^{49}$Mn ($Q_\\mathrm{EC}=7712.42(24)$\nkeV) have been measured with an unprecedented precision. The data reveal a\n16-keV ($1.6\\sigma$) offset in the adopted Atomic Mass Evaluation 2012 value of\n$^{49}$Mn suggesting the need for further measurements to verify the breakdown\nof the quadratic form of the isobaric multiplet mass equation. Precisely\nmeasured $Q_\\mathrm{EC}$ values confirm that the pairing effect in the Coulomb\nenergies is quenched when entering the $f_{7/2}$ shell and reaches a minimum in\nthe midshell.", + "category": "nucl-ex" + }, + { + "text": "Investigating nuclear structure near $N = 32$ and $N = 34$: Precision\n mass measurements of neutron-rich Ca, Ti and V isotopes: Nuclear mass measurements of isotopes are key to improving our understanding\nof nuclear structure across the chart of nuclides, in particular for the\ndetermination of the appearance or disappearance of nuclear shell closures. We\npresent high-precision mass measurements of neutron-rich Ca, Ti and V isotopes\nperformed at the TITAN and LEBIT facilities. These measurements were made using\nthe TITAN multiple-reflection time-of-flight mass spectrometer (MR-ToF-MS) and\nthe LEBIT 9.4T Penning trap mass spectrometer. In total, 13 masses were\nmeasured, eight of which represent increases in precision over previous\nmeasurements. These measurements refine trends in the mass surface around $N =\n32$ and $N = 34$, and support the disappearance of the $N = 32$ shell closure\nwith increasing proton number. Additionally, our data does not support the\npresence of a shell closure at $N = 34$.", + "category": "nucl-ex" + }, + { + "text": "14Be(p,n)14B reaction at 69 MeV in inverse kinematics: A Gamow-Teller (GT) transition from the drip-line nucleus 14Be to 14B was\nstudied via the (p,n) reaction in inverse kinematics using a secondary 14Be\nbeam at 69 MeV/nucleon. The invariant mass method is employed to reconstruct\nthe energy spectrum. A peak is observed at an excitation energy of 1.27(2) MeV\nin 14B, together with bumps at 2.08 and 4.06(5) MeV. The observed forward\npeaking of the state at 1.27 MeV and a good description for the differential\ncross section, obtained with a DWBA calculation provide support for the 1+\nassignment to this state. By extrapolating the cross section to zero momentum\ntransfer the GT-transition strength is deduced. The value is found to compare\nwell with that reported in a beta-delayed neutron emission study.", + "category": "nucl-ex" + }, + { + "text": "LENDA, a Low Energy Neutron Detector Array for experiments with\n radioactive beams in inverse kinematics: The Low Energy Neutron Detector Array (LENDA) is a neutron time-of-flight\n(TOF) spectrometer developed at the National Superconducting Cyclotron Lab-\noratory (NSCL) for use in inverse kinematics experiments with rare isotope\nbeams. Its design has been motivated by the need to study the spin-isospin\nresponse of unstable nuclei using (p, n) charge-exchange reactions at\nintermediate energies (> 100 MeV/u). It can be used, however, for any reaction\nstudy that involves emission of low energy neutrons (150 keV - 10 MeV). The\narray consists of 24 plastic scintillator bars and is capable of registering\nthe recoiling neutron energy and angle with high detection efficiency. The\nneutron energy is determined by the time-of-flight technique, while the\nposition of interaction is deduced using the timing and energy information from\nthe two photomultipliers of each bar. A simple test setup utilizing radioactive\nsources has been used to characterize the array. Results of test measurements\nare compared with simulations. A neutron energy threshold of < 150 keV, an\nintrinsic time (position) resolution of \\sim 400 ps (\\sim 6 cm) and an\nefficiency > 20 % for neutrons below 4 MeV have been obtained.", + "category": "nucl-ex" + }, + { + "text": "Geo-neutrinos and the Radioactive Power of the Earth: Chemical and physical Earth models agree little as to the radioactive power\nof the planet. Each predicts a range of radioactive powers, overlapping\nslightly with the other at about 24 TW, and together spanning 14-46 TW.\nApproximately 20 % of this radioactive power (3-8 TW) escapes to space in the\nform of geo-neutrinos. The remaining 11-38 TW heats the planet with significant\ngeo-dynamical consequences, appearing as the radiogenic component of the 43-49\nTW surface heat flow. The non-radiogenic component of the surface heat flow\n(5-38 TW) is presumably primordial, a legacy of the formation and early\nevolution of the planet. A constraining measurement of radiogenic heating\nprovides insights to the thermal history of the Earth and potentially\ndiscriminates chemical and physical Earth models. Radiogenic heating in the\nplanet primarily springs from unstable nuclides of uranium, thorium, and\npotassium. The paths to their stable daughter nuclides include nuclear beta\ndecays, producing geo-neutrinos. Large sub-surface detectors efficiently record\nthe energy but not the direction of the infrequent interactions of the highest\nenergy geo-neutrinos, originating only from uranium and thorium. The measured\nenergy spectrum of the interactions estimates the relative amounts of these\nheat-producing elements, while the intensity estimates planetary radiogenic\npower. Recent geo-neutrino observations in Japan and Italy find consistent\nvalues of radiogenic heating. The combined result mildly excludes the lowest\nmodel values of radiogenic heating and, assuming whole mantle convection,\nidentifies primordial heat loss. Future observations have the potential to\nmeasure radiogenic heating with better precision, further constraining\ngeological models and the thermal evolution of the Earth.", + "category": "nucl-ex" + }, + { + "text": "Recent results from BRAHMS: The BRAHMS collaboration ended its data collection program in 2006. We are\nnow well advanced in the analysis of a comprehensive set of data that spans\nsystems ranging in mass from p+p to Au+Au and in energy from $\\sqrt{s_{NN}} =\n62.4$ to 200 GeV. Our analysis has taken two distinct paths: we explore the\nrapidity dependence of intermediate and high-transverse-momentum,\nidentified-particle production, thus helping to characterize the\nstrongly-interacting quark-gluon plasma (sQGP) formed at RHIC; we also explore\nparticle yields at lower transverse momentum to develop a systematic\nunderstanding of bulk particle production at RHIC energies.", + "category": "nucl-ex" + }, + { + "text": "Measurement of inclusive electrons from open heavy-flavor hadron decays\n in $p$+$p$ collisions at $\\sqrt{s} = 200$ GeV with the STAR detector: We report a new measurement of the production cross section for inclusive\nelectrons from open heavy-flavor hadron decays as a function of transverse\nmomentum ($p_{\\rm T}$) at mid-rapidity ($|y|<$ 0.7) in $p$+$p$ collisions at\n$\\sqrt{s} = 200$ GeV. The result is presented for 2.5 $ 0.7 measured in Au+Em and Pb+Em collisions at AGS and SPS energies\nare analyzed using Fourier transformation method and maximum entropy one. The\ndependences of these spectra on the number of fast target protons (g-particles)\nare studied. They show visually some plateau and \"shoulder\" which are at least\nthree selected points on the distributions. The plateau seems wider in Pb+Em\nreactions. The existing of plateau is expected for the parton models. The\nmaximum entropy method confirms the existence of the plateau and the shoulder\nof the distributions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the $\u03bd_e$ and Total $^{8}$B Solar Neutrino Fluxes with\n the Sudbury Neutrino Observatory Phase I Data Set: This article provides the complete description of results from the Phase I\ndata set of the Sudbury Neutrino Observatory (SNO). The Phase I data set is\nbased on a 0.65 kt-year exposure of heavy water to the solar $^8$B neutrino\nflux. Included here are details of the SNO physics and detector model,\nevaluations of systematic uncertainties, and estimates of backgrounds. Also\ndiscussed are SNO's approach to statistical extraction of the signals from the\nthree neutrino reactions (charged current, neutral current, and elastic\nscattering) and the results of a search for a day-night asymmetry in the\n$\\nu_e$ flux. Under the assumption that the $^8$B spectrum is undistorted, the\nmeasurements from this phase yield a solar $\\nu_e$ flux of $\\phi(\\nu_e) =\n 1.76^{+0.05}_{-0.05}{(stat.)}^{+0.09}_{-0.09} {(syst.)}\n \\times 10^{6}$ cm$^{-2}$ s$^{-1}$, and a non-$\\nu_e$ component\n$\\phi(\\nu_{\\mu\\tau}) =\n 3.41^{+0.45}_{-0.45}{(stat.)}^{+0.48}_{-0.45} {(syst.)}\n \\times 10^{6}$ cm$^{-2}$ s$^{-1}$. The sum of these components provides a\ntotal flux in excellent agreement with the predictions of Standard Solar\nModels. The day-night asymmetry in the $\\nu_e$ flux is found to be $A_{e} = 7.0\n\\pm 4.9 \\mathrm{(stat.)^{+1.3}_{-1.2}}% \\mathrm{(sys.)}$, when the asymmetry in\nthe total flux is constrained to be zero.", + "category": "nucl-ex" + }, + { + "text": "Direct photons at low $p_{T}$ measured in PHENIX: Direct photon spectra measured at small $p_T$ in p+p, d+Au and Au+Au\ncollisions at $\\sqrt{s_{NN}}=200$ GeV are presented. Several measurement\ntechniques including statistical subtraction, tagging, and internal and\nexternal conversion were applied and found to produce consistent results. The\np+p and d+Au results are found to be in very good agreement with pQCD\npredictions over the entire $p_T$ range. No excess of direct photons in Au+Au\ncollisions with respect to binary scaled d+Au data is observed within\nsystematic errors.", + "category": "nucl-ex" + }, + { + "text": "Study of high-pT charged particle suppression in PbPb compared to pp\n collisions at sqrt(sNN)=2.76 TeV: The transverse momentum spectra of charged particles have been measured in pp\nand PbPb collisions at sqrt(sNN) = 2.76 TeV by the CMS experiment at the LHC.\nIn the transverse momentum range pt = 5-10 GeV/c, the charged particle yield in\nthe most central PbPb collisions is suppressed by up to a factor of 5 compared\nto the pp yield scaled by the number of incoherent nucleon-nucleon collisions.\nAt higher pt, this suppression is significantly reduced, approaching roughly a\nfactor of 2 for particles with pt in the range pt=40-100 GeV/c.", + "category": "nucl-ex" + }, + { + "text": "Thermonuclear reaction rate of $^{29}$Si(p,$\u03b3$)$^{30}$P: The thermonuclear rate of the $^{29}$Si(p,$\\gamma$)$^{30}$P reaction impacts\nthe $^{29}$Si abundance in classical novae. A reliable reaction rate is\nessential for testing the nova paternity of presolar stardust grains. At\npresent, the fact that no classical nova grains have been unambiguously\nidentified in primitive meteorites among thousands of grains studied is\npuzzling, considering that classical novae are expected to be prolific\nproducers of dust grains. We investigated the $^{29}$Si $+$ $p$ reaction at\ncenter-of-mass energies of $200$ $-$ $420$~keV, and present improved values for\nresonance energies, level excitation energies, resonance strengths, and\nbranching ratios. One new resonance was found at a center-of-mass energy of\n$303$ keV. For an expected resonance at $215$~keV, an experimental upper limit\ncould be determined for the strength. We evaluated the level structure near the\nproton threshold, and present new reaction rates based on all the available\nexperimental information. Our new reaction rates have much reduced\nuncertainties compared to previous results at temperatures of $T$ $\\ge$\n$140$~MK, which are most important for classical nova nucleosynthesis. Future\nexperiments to improve the reaction rates at lower temperatures are discussed.", + "category": "nucl-ex" + }, + { + "text": "Determination of integral cross sections of 3H in Al foils monitors\n irradiated by protons with energies ranging from 40 to 2600 MeV: Results of t production in Al foil monitors are presented. These foils have\nbeen irradiated by protons of different energies in a range of 0.04 - 2.6 GeV.\nThe irradiations were carried out at the ITEP accelerator U-10 under the ISTC\nProject 3266 during 2006 - 2009. t has been extracted from Al foils using an\nA307 Sample Oxidizer. The values of the Al(p,x)t cross sections obtained in\nthese experiments are compared with data measured at other laboratories and\nwith results of simulations by the MCNP6 radiation transport code using the\nCEM03.03 event generator.", + "category": "nucl-ex" + }, + { + "text": "First results from Au+Au collisions at $\\sqrt(s_{NN})$ = 9.2 GeV in STAR: One of the primary aims of heavy-ion collisions is to map the QCD phase\ndiagram and search for different phases and phase boundaries. RHIC Energy Scan\nProgram was launched to address this goal by studying heavy-ion collisions at\ndifferent center of mass energies. The first test run with Au+Au collisions at\n$\\sqrt{s_{NN}}$ = 9.2 GeV took place in early 2008. The large acceptance STAR\ndetector has collected few thousands minimum bias collisions at this beam\nenergy. We present the first results for identified particle yields and\nparticle ratios. The results for the azimuthal anisotropy parameters $v_1$ and\n$v_2$ and those from pion interferometry measurements are also discussed in\nthis paper. These results are compared to data from the SPS at similar beam\nenergies.", + "category": "nucl-ex" + }, + { + "text": "Sensitivity and discovery potential of the proposed nEXO experiment to\n neutrinoless double beta decay: The next-generation Enriched Xenon Observatory (nEXO) is a proposed\nexperiment to search for neutrinoless double beta ($0\\nu\\beta\\beta$) decay in\n$^{136}$Xe with a target half-life sensitivity of approximately $10^{28}$ years\nusing $5\\times10^3$ kg of isotopically enriched liquid-xenon in a time\nprojection chamber. This improvement of two orders of magnitude in sensitivity\nover current limits is obtained by a significant increase of the $^{136}$Xe\nmass, the monolithic and homogeneous configuration of the active medium, and\nthe multi-parameter measurements of the interactions enabled by the time\nprojection chamber. The detector concept and anticipated performance are\npresented based upon demonstrated realizable background rates.", + "category": "nucl-ex" + }, + { + "text": "Isolated photon production in $\\sqrt{s_{NN}}$ = 2.76 TeV PbPb collisions\n as a function of transverse energy and reaction centrality: In studies of the dense medium produced in ultra-relativistic heavy ion\ncollisions, photons are important hard probes, since they are not expected to\nbe modified by the medium. The measurement of isolated prompt photon production\nin PbPb collisions provides a test of perturbative quantum chromodynamics\n(pQCD) and the information to constrain the nuclear parton distribution\nfunctions. CMS has shown photon purity measurement capabilities in pp\ncollisions using the shower shape templates. In PbPb co llisions at CMS, this\ntechnique was applied for the first time in heavy ion collisions. We report the\nfirst measurement of the transverse momentum spectra of isolated photons with\npT from 20 GeV/c to 80 GeV/c in PbPb collisions at $\\sqrt{s_{NN}}$ =2.76 TeV.\nThe centrality dependence of the nuclear modification factor is also reported\nby comparing the result to the photon spectrum of pp reference which is\ncomputed from NLO calculations.", + "category": "nucl-ex" + }, + { + "text": "Chemical Analyses of Silicon Aerogel Samples: After five years of operating, two Aerogel counters: A1 and A2, taking data\nin Hall A at Jefferson Lab, suffered a loss of performance. In this note\npossible causes of degradation have been studied. In particular, various\nchemical and physical analyses have been carried out on several Aerogel tiles\nand on adhesive tape in order to reveal the presence of contaminants.", + "category": "nucl-ex" + }, + { + "text": "Precision Measurement of the Neutron Spin Asymmetries and Spin-dependent\n Structure Functions in the Valence Quark Region: We report on measurements of the neutron spin asymmetries $A_{1,2}^n$ and\npolarized structure functions $g_{1,2}^n$ at three kinematics in the deep\ninelastic region, with $x=0.33$, 0.47 and 0.60 and $Q^2=2.7$, 3.5 and 4.8\n(GeV/c)$^2$, respectively. These measurements were performed using a 5.7 GeV\nlongitudinally-polarized electron beam and a polarized $^3$He target. The\nresults for $A_1^n$ and $g_1^n$ at $x=0.33$ are consistent with previous world\ndata and, at the two higher $x$ points, have improved the precision of the\nworld data by about an order of magnitude. The new $A_1^n$ data show a zero\ncrossing around $x=0.47$ and the value at $x=0.60$ is significantly positive.\nThese results agree with a next-to-leading order QCD analysis of previous world\ndata. The trend of data at high $x$ agrees with constituent quark model\npredictions but disagrees with that from leading-order perturbative QCD (pQCD)\nassuming hadron helicity conservation. Results for $A_2^n$ and $g_2^n$ have a\nprecision comparable to the best world data in this kinematic region. Combined\nwith previous world data, the moment $d_2^n$ was evaluated and the new result\nhas improved the precision of this quantity by about a factor of two. When\ncombined with the world proton data, polarized quark distribution functions\nwere extracted from the new $g_1^n/F_1^n$ values based on the quark parton\nmodel. While results for $\\Delta u/u$ agree well with predictions from various\nmodels, results for $\\Delta d/d$ disagree with the leading-order pQCD\nprediction when hadron helicity conservation is imposed.", + "category": "nucl-ex" + }, + { + "text": "Isospin Mixing and the Cubic Isobaric Multiplet Mass Equation in the\n Lowest T = 2, A = 32 Quintet: The isobaric multiplet mass equation (IMME) is known to break down in the\nfirst T = 2, A = 32 isospin quintet. In this work we combine high-resolution\nexperimental data with state-of-the-art shell-model calculations to investigate\nisospin mixing as a possible cause for this violation. The experimental data\nare used to validate isospin-mixing matrix elements calculated with newly\ndeveloped shell-model Hamiltonians. Our analysis shows that isospin mixing with\nnonanalog T = 1 states contributes to the IMME breakdown, making the\nrequirement of an anomalous cubic term inevitable for the multiplet.", + "category": "nucl-ex" + }, + { + "text": "Open charm hadron measurement in p+p and Au+Au collisions at\n $\\sqrt{s_{NN}}$ = 200 GeV in STAR: We present the measurements of $D^0$ and $D^*$ in p+p and $D^0$ in Au+Au\ncollisions via hadronic decays $D^{0}\\rightarrow K^{-}\\pi^{+}$,\n$D^{*+}\\rightarrow D^{0}\\pi^{+}\\rightarrow K^{-}\\pi^{+}\\pi^{+}$ in mid-rapidity\n$|y|<1$ at $\\sqrt{s_{_{\\rm NN}}}$ = 200 GeV, covering $p_T$ from 0.2 to 6\nGeV/$c$ in p+p and 0.4 to 5 GeV/$c$ in Au+Au, respectively. The charm pair\nproduction cross section per nucleon-nucleon collision at mid rapidity is\nmeasured to be 202 $\\pm$ 56 (stat.) $\\pm$ 40 (sys.) $\\pm$ 20 (norm.) $\\mu$b in\np+p and 186 $\\pm$ 22 (stat.) $\\pm$ 30 (sys.) $\\pm$ 18 (norm.) $\\mu$b in Au+Au\nminimum bias collisions. The number of binary collisions scaling of charm cross\nsection indicates that charm is produced via initial hard scatterings. No\nsuppression of $D^0$ $R_{AA}$ in Au+Au 0-80% minbias collisions is observed at\n$p_T$ below 3 GeV/$c$. Blast-wave predictions with light-quark hadron\nparameters are different from data, which may indicate that $D^0$ decouples\nearlier from the medium than the light-quark hadrons.", + "category": "nucl-ex" + }, + { + "text": "Absolute resonance strengths in the 6,7Li(alpha,gamma)10,11B reactions: The absolute strengths of the Ea=1175keV resonance in the 6Li(a,g)10B\nreaction and of the Ea=814 keV resonance in the 7Li(a,g)11B reaction have been\nmeasured to $\\omega\\gamma$=366+-38 meV and $\\omega\\gamma$=300+-32 meV,\nrespectively, in good agreement with previous values.\n These resonances can be used to measure the absolute acceptance of the recoil\nseparator ERNA to a precision of about 10%.", + "category": "nucl-ex" + }, + { + "text": "Shape coexistence near the neutron number N=20: First identification of\n the E0 decay from the deformed 0^+_2 state in 30Mg: The 1789 keV level in 30Mg was identified as the first excited 0^+ state by\nmeasuring its E0 transition to the ground state. The measured small value of\nrho^2(E0,0^+_2 --> 0^+_1) = 5.7(14) x 10^-3 implies a very small mixing of\ncompeting configurations with largely different intrinsic quadrupole\ndeformation near N=20. Axially symmetric Beyond-Mean-Field configuration mixing\ncalculations identify the ground state of 30Mg to be based on neutron\nconfigurations below the N=20 shell closure, while the excited 0^+ state mainly\nconsists of a two neutrons excitated into the nu1 f_{7/2} orbital. Using a\ntwo-level model, a mixing amplitude of 0.08(4) can be derived.", + "category": "nucl-ex" + }, + { + "text": "Consistency of 8B neutrino spectra: We identify and quantify systematic effects not accounted for in two previous\nmeasurements of the alpha-alpha relative-energy distribution in the beta decay\nof 8B, which can explain the apparent disagreement with respect to two newer\nmeasurements. This settles a current dispute concerning the shape of the 8B\nneutrino spectrum of importance to solar-neutrino studies.", + "category": "nucl-ex" + }, + { + "text": "Search for Periodic Modulations of the Rate of Double-Beta Decay of\n $^{100}$Mo in the NEMO-3 Detector: Double-beta decays of $^{100}$Mo from the 6.0195-year exposure of a 6.914 kg\nhigh-purity sample were recorded by the NEMO-3 experiment that searched for\nneutrinoless double-beta decays. These ultra-rare transitions to $^{100}$Ru\nhave a half-life of approximately $7\\times10^{18}$ years, and have been used to\nconduct the first ever search for periodic variations of this decay mode. The\nLomb-Scargle periodogram technique, and its error-weighted extension, were\nemployed to look for periodic modulations of the half-life. Monte Carlo\nmodeling was used to study the modulation sensitivity of the data over a broad\nrange of amplitudes and frequencies. Data show no evidence of modulations with\namplitude greater than 2.5% in the frequency range of $0.33225\\,{\\rm y^{-1}}$\nto $365.25\\,{\\rm y^{-1}}$.", + "category": "nucl-ex" + }, + { + "text": "Projectile fragment emission in fragmentation of $^{56}$Fe on C, Al,and\n CH$_{2}$ targets at 471 A MeV: The emission angle and the transverse momentum distributions of projectile\nfragments produced in fragmentation of $^{56}$Fe on CH$_{2}$, C, and Al targets\nat 471 A MeV are measured. It is found that for the same target the average\nvalue and width of angular distribution decrease with increase of the\nprojectile fragment charge, and for the same projectile fragment the average\nvalue of the distribution increases and the width of the distribution decreases\nwith increasing the target charge number. The transverse momentum distribution\nof projectile fragment can be explained by a single Gaussian distribution and\nthe averaged transverse momentum per nucleon decreases with the increase of the\ncharge of projectile fragment. The cumulated squared transverse momentum\ndistribution of projectile fragment can be well explained by a single Rayleigh\ndistribution. The temperature parameter of emission source of projectile\nfragment, calculated from the cumulated squared transverse momentum\ndistribution, decreases with the increase of the size of projectile fragment.", + "category": "nucl-ex" + }, + { + "text": "High PT Physics with the STAR Experiment at RHIC: The STAR experiment at RHIC is a TPC-based, general purpose detector designed\nto obtain charged particle spectra, with an emphasis on hadrons over a large\nphase space. An electromagnetic calorimeter provides measurement of electrons,\nphotons, pi-zeros and jets. Data-taking with Au+Au collisions at sqrt(s)= 200\nGeV/c**2 begins in Fall 1999. The STAR experiment's investigation of techniques\nand signals using hard probes to study the high energy-density matter at RHIC\nand to search for quark-gluon plasma formation will be described.", + "category": "nucl-ex" + }, + { + "text": "First Online Mass Measurements of Isobar Chains via Multi-Reflection\n Time-of-Flight Mass Spectrograph Coupled with GARIS-II: Using a mulit-reflection time-of-flight mass spectrograph (MRTOF-MS) located\nafter a gas cell coupled with the gas-filled recoil ion separator GARIS-II, the\nmasses of several heavy nuclei have been directly and precisely measured. The\nnuclei were produced via fusion-evaporation reactions and separated from\nprojectile-like and target-like particles using GARIS-II before being stopped\nin a helium-filled gas cell. Time-of-flight spectra for three isobar chains,\n205Fr-205Rn-205At-205Po, 206Fr-206Rn-206At and 201Rn-201At-201Po-201Bi, were\nobserved. Precision atomic mass values were determined for 205,206Fr, 201At,\nand 201Po.", + "category": "nucl-ex" + }, + { + "text": "Heavy Flavor Production at PHENIX at RHIC: A study of heavy flavor production in different collision systems in various\nkinematic regions presents an opportunity to probe cold nuclear medium and hot\ndense matter effects. Results from the PHENIX experiment on $J/\\psi$ and open\ncharm production in Au+Au and Cu+Cu collisions at $\\sqrt{s_{NN}}$ =200 GeV are\npresented. The data show strong $J/\\psi$ suppression in central AA collisions,\nsimilar to NA50 results, and strong suppression in high $p_T$ open charm\nproduction. The $J/\\psi$ production in Au+Au and d+Au collisions is compared to\nunderstand the cold nuclear medium effects. The data show significant cold\nnuclear effects in charm production in d+Au collisions at forward and backward\nrapidity ranges.", + "category": "nucl-ex" + }, + { + "text": "Integral measurement of the $^{12}$C(n,p)$^{12}$B reaction up to 10 GeV: The integral measurement of the $^{12}$C(n,p)$^{12}$B reaction was performed\nat the neutron time of flight facility n_TOF at CERN. The total number of\n$^{12}$B nuclei produced per neutron pulse of the n_TOF beam was determined\nusing the activation technique in combination with a time of flight technique.\nThe cross section is integrated over the n_TOF neutron energy spectrum from\nreaction threshold at 13.6 MeV to 10 GeV. Having been measured up to 1 GeV on\nbasis of the $^{235}$U(n,f) reaction, the neutron energy spectrum above 200 MeV\nhas been reevaluated due to the recent extension of the cross section reference\nfor this particular reaction, which is otherwise considered a standard up to\n200 MeV. The results from the dedicated GEANT4 simulations have been used to\nevaluate the neutron flux from 1 GeV up to 10 GeV. The experimental results\nrelated to the $^{12}$C(n,p)$^{12}$B reaction are compared with the evaluated\ncross sections from major libraries and with the predictions of different\nGEANT4 models, which mostly underestimate the $^{12}$B production. On the\ncontrary, a good reproduction of the integral cross section derived from\nmeasurements is obtained with TALYS-1.6 calculations, with optimized\nparameters.", + "category": "nucl-ex" + }, + { + "text": "Differential Cross Section for $\u03b3d \\rightarrow \u03c9d$ using\n CLAS at Jefferson Lab: The cross section for coherent $\\omega$-meson photoproduction off the\ndeuteron has been measured for the first time as a function of the momentum\ntransfer $t = (P_{\\gamma}-P_{\\omega})^2$ and photon energy $E_{\\gamma}$ using\nthe CLAS detector at the Thomas Jefferson National Accelerator Facility. The\ncross sections are measured in the energy range $1.4 < E_{\\gamma} < 3.4$ GeV. A\nmodel based on $\\omega-N$ rescattering is consistent with the data at low and\nintermediate momentum transfer, $|t|$. For $2.8 < E_{\\gamma} < 3.4$ GeV, the\ntotal cross-section of $\\omega-N$ scattering, based on fits within the\nframework of the Vector Meson Dominance model, is in the range of 30-40 mb.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the 18Ne(a,p_0)21Na reaction cross section in the burning\n energy region for X-ray bursts: The 18Ne(a,p)21Na reaction provides one of the main HCNO-breakout routes into\nthe rp-process in X-ray bursts. The 18Ne(a,p_0)21Na reaction cross section has\nbeen determined for the first time in the Gamow energy region for peak\ntemperatures T=2GK by measuring its time-reversal reaction 21Na(p,a)18Ne in\ninverse kinematics. The astrophysical rate for ground-state to ground-state\ntransitions was found to be a factor of 2 lower than Hauser-Feshbach\ntheoretical predictions. Our reduced rate will affect the physical conditions\nunder which breakout from the HCNO cycles occurs via the 18Ne(a,p)21Na\nreaction.", + "category": "nucl-ex" + }, + { + "text": "Centrality Dependence of Kaon Yields in Si+A and Au+Au Collisions at\n Relativistic Energies: Charged kaon production has been measured in Si+Al and Si+Au collisions at\n14.6 A GeV/c, and Au+Au collisions at 11.1 A GeV/c by Experiments 859 and 866\n(the E--802 Collaboration) at the BNL AGS. Invariant transverse mass spectra\nand rapidity distributions for both K+ and K- are presented. The centrality\ndependence of rapidity-integrated kaon yields is studied. Strangeness\nenhancement is observed as an increase in the slope of the kaon yield with the\ntotal number of participants as well as the yield per participant. The\nenhancement starts with peripheral Si+Al and Si+Au collisions (relative to N+N)\nand appears to saturate for a moderate number of participating nucleons in\nSi+Au collisions. It is also observed to increase slowly with centrality in\nAu+Au collisions, to a level in the most central Au+Au collisions that is\ngreater than that found in central Si+A collisions. The enhancement factor for\n$K^+$ production are 3.0 +-0.2(stat.) +-0.4(syst.) and 4.0 +-0.3(stat.)\n+-0.5(syst.), respectively, for the most central 7% Si+Au collisions and the\nmost central 4% Au+Au collisions relative to N+N at the correponding beam\nenergy.", + "category": "nucl-ex" + }, + { + "text": "Single-particle shell strengths near the doubly magic nucleus $^{56}$Ni\n and the $^{56}$Ni(p,$\u03b3$)$^{57}$Cu reaction rate in explosive\n astrophysical burning: Angle-integrated cross-section measurements of the $^{56}$Ni(d,n) and (d,p)\nstripping reactions have been performed to determine the single-particle\nstrengths of low-lying excited states in the mirror nuclei pair\n$^{57}$Cu-$^{57}$Ni situated adjacent to the doubly magic nucleus $^{56}$Ni.\nThe reactions were studied in inverse kinematics utilizing a beam of\nradioactive $^{56}$Ni ions in conjunction with the GRETINA $\\gamma$-array.\nSpectroscopic factors are compared with new shell-model calculations using a\nfull $pf$ model space with the GPFX1A Hamiltonian for the isospin-conserving\nstrong interaction plus Coulomb and charge-dependent Hamiltonians. These\nresults were used to set new constraints on the $^{56}$Ni(p,$\\gamma$)$^{57}$Cu\nreaction rate for explosive burning conditions in x-ray bursts, where $^{56}$Ni\nrepresents a key waiting point in the astrophysical rp-process.", + "category": "nucl-ex" + }, + { + "text": "Study of internal structures of 9,10Be and 10B in scattering of 4He from\n 9Be: A study of inelastic scattering and single-particle transfer reactions was\nperformed by an alpha beam at 63 MeV on a 9$Be target. Angular distributions of\nthe differential cross sections for the 9Be(4He,4He')9Be*, 9Be(4He,3He)10Be and\n9Be(4He,t)10B reactions were measured. Experimental angular distributions of\nthe differential cross sections for the ground state and a few low-lying states\nwere analyzed in the framework of the optical model, coupled channels and\ndistorted-wave Born approximation. An analysis of the obtained spectroscopic\nfactors was performed.", + "category": "nucl-ex" + }, + { + "text": "Measurements of $^{160}$Dy($p,\u03b3$) at energies relevant for\n astrophysical $\u03b3$ process: Rare information on photodisintegration reactions of nuclei with mass numbers\n$A \\approx 160$ at astrophysical conditions impedes our understanding of the\norigin of $p$-nuclei. Experimental determination of the key ($p,\\gamma$) cross\nsections has been playing an important role to verify nuclear reaction models\nand to provide rates of relevant ($\\gamma,p$) reactions in $\\gamma$-process. In\nthis paper we report the first cross section measurements of\n$^{160}$Dy($p,\\gamma$)$^{161}$Ho and $^{161}$Dy($p,n$)$^{161}$Ho in the beam\nenergy range of 3.4 - 7.0 MeV, partially covering the Gamow window. Such\ndeterminations are possible by using two targets with various isotopic\nfractions. The cross section data can put a strong constraint on the nuclear\nlevel densities and gamma strength functions for $A \\approx$ 160 in the\nHauser-Feshbach statistical model. Furthermore, we find the best parameters for\nTALYS that reproduce the A $\\thicksim$ 160 data available,\n$^{160}$Dy($p,\\gamma$)$^{161}$Ho and $^{162}$Er($p,\\gamma$)$^{163}$Tm, and\nrecommend the constrained $^{161}$Ho($\\gamma,p$)$^{160}$Dy reaction rates over\na wide temperature range for $\\gamma$-process network calculations. Although\nthe determined $^{161}$Ho($\\gamma$, p) stellar reaction rates at the\ntemperature of 1 to 2 GK can differ by up to one order of magnitude from the\nNON-SMOKER predictions, it has a minor effect on the yields of $^{160}$Dy and\naccordingly the $p$-nuclei, $^{156,158}$Dy. A sensitivity study confirms that\nthe cross section of $^{160}$Dy($p$, $\\gamma$)$^{161}$Ho is measured precisely\nenough to predict yields of $p$-nuclei in the $\\gamma$-process.", + "category": "nucl-ex" + }, + { + "text": "Estimation of radiative half-life of $^{229m}$Th by half-life\n measurement of other nuclear excited states in $^{229}$Th: We perform coincidence measurements between $\\alpha$ particles and $\\gamma$\nrays from a $^{233}$U source to determine the half-lives of the excited state\nin a $^{229}$Th nucleus. We first prove that the half-lives of 42.43- and\n164.53-keV states are consistent with literature values, whereas that of the\n97.14-keV state (93(7) ps) deviates from a previously measured value (147(12)\nps). The half-lives of 71.83- and 163.25-keV states are determined for the\nfirst time. Based on the obtained half-lives and the Alaga rule, we estimate\nthe radiative half-life of the low-energy isomeric state ($^{229m}$Th) to be\n$5.0(11)\\times10^{3}$ s, which is one of the key parameters for the frequency\nstandard based on $^{229}$Th.", + "category": "nucl-ex" + }, + { + "text": "The measurement of non-photonic electrons in STAR: The measurements of non-photonic electrons (NPE), mainly produced by\nsemileptonic decays of D and B mesons, provide information on heavy quarks\nproduction as well as properties of nuclear matter produced in heavy ion\ncollisons. In order to interpret the NPE measurements it is important to\ndetermine the relative charm and bottom contribution to the NPE spectrum. In\nthis proceedings we present the measurements of NPE spectra and NPE-hadron\nazimuthal correlations in p+p collisions at $\\sqrt{s}$=200 GeV and at\n$\\sqrt{s}$=500 GeV. NPE-hadron correlations allow extraction of the B decay\ncontribution to the NPE. The B decay contribution is comparable to the\ncontribution from the D meson decay at $\\sqrt{s}$=200 GeV at p$_T$ higher than\n5 GeV/c, and is about 60% at $\\sqrt{s}$=500 GeV at p$_T$ higher than 5 GeV/c.\nSTAR measured NPE spectrum in p+p collisions as well as relative constribution\nof bottom decays to the spectrum is consistent with FONLL pQCD calculations.\nThe preliminary results of NPE spectra and NPE-hadron correlations in Au+Au\ncollisions at $\\sqrt{s}$=200 GeV is shown.", + "category": "nucl-ex" + }, + { + "text": "Bose-Einstein correlations of pion pairs in central Pb+Pb collisions at\n CERN SPS energies: Measurements of Bose-Einstein correlations of pion pairs in central Pb+Pb\ncollisions were performed with the NA49 detector at the CERN SPS for beam\nenergies of 20A, 30A, 40A, 80A, and 158A GeV. Correlation functions were\nmeasured in the longitudinally co-moving ``out-side-long'' reference frame as a\nfunction of rapidity and transverse momentum in the forward hemisphere of the\nreaction. Radius and correlation strength parameters were obtained from fits of\na Gaussian parametrization. The results show a decrease of the radius\nparameters with increasing transverse momentum characteristic of strong radial\nflow in the pion source. No striking dependence on pion-pair rapidity or beam\nenergy is observed. Static and dynamic properties of the pion source are\nobtained from simultaneous fits with a blast-wave model to radius parameters\nand midrapidity transverse momentum spectra. Predictions of hydrodynamic and\nmicroscopic models of Pb+Pb collisions are discussed.", + "category": "nucl-ex" + }, + { + "text": "Excess of charged over neutral $K$ meson production in high-energy\n collisions of atomic nuclei: Collisions of atomic nuclei at relativistic velocities produce new particles,\npredominantly mesons containing one valence quark and one valence anti-quark.\nThese particles are produced in strong interactions, which preserve an\napproximate symmetry between up ($u$) and down ($d$) quarks. In the case of $K$\nmeson production, if this symmetry were exact, it would result in equal numbers\nof charged ($K^+$ and $K^-$) and neutral ($K^0$ and $\\overline K^0$) mesons in\nthe final state. In this Letter, we report a measurement of the relative\nabundance of charged over neutral $K$ meson production in collisions of argon\nand scandium nuclei at a center-of-mass energy of 11.9~GeV per nucleon pair. We\nfind that production of $\\mathit{K^+}$ and $\\mathit{K^-}$ mesons at\nmid-rapidity displays a significant excess of $(23.3\\pm 5.5)\\%$ relative to\nthat of the neutral $K$ mesons. The origin of this unexpected excess remains to\nbe elucidated.", + "category": "nucl-ex" + }, + { + "text": "Search for solar axions via axion-photon coupling with the Majorana\n Demonstrator: Axions were originally proposed to explain the strong-CP problem in QCD.\nThrough the axion-photon coupling, the Sun could be a major source of axions,\nwhich could be measured in solid state detection experiments with enhancements\ndue to coherent Primakoff-Bragg scattering. The Majorana Demonstrator\nexperiment has searched for solar axions with a set of $^{76}$Ge-enriched high\npurity germanium detectors using a 33 kg-yr exposure collected between Jan.\n2017 and Nov. 2019. A temporal-energy analysis gives a new limit on the\naxion-photon coupling as $g_{a\\gamma}<1.45\\times 10^{-9}$ GeV$^{-1}$ (95% C.I.)\nfor axions with mass up to 100 eV/$c^2$. This improves laboratory-based limits\nbetween about 1 eV/$c^2$ and 100 eV/$c^2$.", + "category": "nucl-ex" + }, + { + "text": "Probing the QCD Critical Point with Higher Moments of Net-proton\n Multiplicity Distributions: Higher moments of event-by-event net-proton multiplicity distributions are\napplied to search for the QCD critical point in the heavy ion collisions. It\nhas been demonstrated that higher moments as well as moment products are\nsensitive to the correlation length and directly connected to the thermodynamic\nsusceptibilities computed in the Lattice QCD and Hadron Resonance Gas (HRG)\nmodel. In this paper, we will present measurements for kurtosis ($\\kappa$),\nskewness ($S$) and variance ($\\sigma^{2}$) of net-proton multiplicity\ndistributions at the mid-rapidity ($|y|<0.5$) and $0.4 \\gamma\\gamma channel for\nthe three colliding systems as well as through the eta-->pi^0 pi+ pi- decay\nmode in p+p and d+Au collisions. The nuclear modification factor in d+Au\ncollisions, R_dAu(p_T~1.0-1.1, suggests at most only modest p_T broadening\n(\"Cronin enhancement\"). In central Au+Au reactions, the eta yields are\nsignificantly suppressed, with R_AuAu(pT)~0.2. The ratio of eta to pi^0 yields\nis approximately constant as a function of p_T for the three colliding systems\nin agreement with the high-p_T world average of R_eta/pi^0 \\approx 0.5 in\nhadron-hadron, hadron-nucleus, and nucleus-nucleus collisions for a wide range\nof center-of-mass energies [sqrt(s_NN)~3-1800 GeV] as well as, for high scaled\nmomentum x_p, in e+e- annihilations at sqrt(s)=91.2 GeV. These results are\nconsistent with a scenario where high-p_T eta production in nuclear collisions\nat RHIC is largely unaffected by initial-state effects, but where light-quark\nmesons (pi^0;eta) are equally suppressed due to final-state interactions of the\nparent partons in the dense medium produced in Au+Au reactions.", + "category": "nucl-ex" + }, + { + "text": "Forward-Backward Multiplicity Correlations in sqrt(s_NN)=200 GeV Au+Au\n Collisions: Forward-backward correlations of charged-particle multiplicities in symmetric\nbins in pseudorapidity (eta) are studied in order to gain insight into the\nunderlying correlation structure of particle production in Au+Au collisions.\nThe PHOBOS detector is used to measure integrated multiplicities in bins\ndefined within eta<3, centered at eta and covering an interval Delta-eta. The\nvariance (sigma^2_C) of a suitably defined forward-backward asymmetry variable\nis calculated as a function of eta, Delta-eta, and centrality. It is found to\nbe sensitive to short range correlations, and the concept of ``clustering'' is\nused to interpret comparisons to phenomenological models.", + "category": "nucl-ex" + }, + { + "text": "Isospin transport in 84Kr + 112,124Sn collisions at Fermi energies: Isotopically resolved fragments with Z<=20 have been studied with high\nresolution telescopes in a test run for the FAZIA collaboration. The fragments\nwere produced by the collision of a 84Kr beam at 35 MeV/nucleon with a n-rich\n(124Sn) and a n-poor (112Sn) target. The fragments, detected close to the\ngrazing angle, are mainly emitted from the phase-space region of the\nprojectile. The fragment isotopic content clearly depends on the n-richness of\nthe target and it is a direct evidence of isospin diffusion between projectile\nand target. The observed enhanced neutron richness of light fragments emitted\nfrom the phase-space region close to the center of mass of the system can be\ninterpreted as an effect of isospin drift in the diluted neck region.", + "category": "nucl-ex" + }, + { + "text": "Measuring the Neutron Lifetime Using Magnetically Trapped Neutrons: The neutron beta-decay lifetime plays an important role both in understanding\nweak interactions within the framework of the Standard Model and in theoretical\npredictions of the primordial abundance of 4He in Big Bang Nucleosynthesis. In\nprevious work, we successfully demonstrated the trapping of ultracold neutrons\n(UCN) in a conservative potential magnetic trap. A major upgrade of the\napparatus is nearing completion at the National Institute of Standards and\nTechnology Center for Neutron Research (NCNR). In our approach, a beam of 0.89\nnm neutrons is incident on a superfluid 4He target within the minimum field\nregion of an Ioffe-type magnetic trap. A fraction of the neutrons is\ndownscattered in the helium to energies <200 neV, and those in the appropriate\nspin state become trapped. The inverse process is suppressed by the low phonon\ndensity of helium at temperatures less than 200 mK, allowing the neutron to\ntravel undisturbed. When the neutron decays the energetic electron ionizes the\nhelium, producing scintillation light that is detected using photomultiplier\ntubes. Statistical limitations of the previous apparatus will be alleviated by\nsignificant increases in field strength and trap volume resulting in twenty\ntimes more trapped neutrons.", + "category": "nucl-ex" + }, + { + "text": "A walk along the proton drip-line by $\u03b2$-decay spectroscopy: During the last decade we have carried out a systematic study of the $\\beta$\ndecay of neutron-deficient nuclei, providing rich spectroscopic information of\nimportance for both nuclear structure and nuclear astrophysics. We present an\noverview of the most relevant achievements, including the discovery of a new\nexotic decay mode in the fp-shell, the $\\beta$-delayed $\\gamma$-proton decay in\n$^{56}$Zn, the first observation of the 2$^+$ isomer in $^{52}$Co and the\nlatest results on the heavier systems $^{60}$Ge and $^{62}$Ge. We also report\non our deduced mass excesses in comparison with systematics and a recent\nmeasurement. Finally, we summarise our results on the half-lives of $T_z=$\n-1/2, -1 and -2 neutron-deficient nuclides, and analyse their trend.", + "category": "nucl-ex" + }, + { + "text": "Experimental constraints on non-linearities induced by two-photon\n effects in elastic and inelastic Rosenbluth separations: The effects of two-photon exchange corrections, suggested to explain the\ndifference between measurements of the proton elastic electromagnetic form\nfactors using the polarization transfer and Rosenbluth techniques, have been\nstudied in elastic and inelastic scattering data. Such corrections could\nintroduce epsilon-dependent non-linearities in inelastic Rosenbluth\nseparations, where epsilon is the virtual photon polarization parameter. It is\nconcluded that such non-linear effects are consistent with zero for elastic,\nresonance, and deep-inelastic scattering for all Q^2 and W^2 values measured.", + "category": "nucl-ex" + }, + { + "text": "Energy dependence of femtoscopy properties of pion source in nuclear\n collisions: In the paper energy dependence of femtoscopy characteristics of pion emission\nregion at freeze-out is investigated for collisions of various ions and for all\nexperimentally available energies. For the first time the normalized values of\nradii and volume of source are used for energy dependence. This approach allows\nus to expand the set of interaction types, in particular, on non-symmetrical\nnucleus-nucleus collisions which can be studied in the framework of common\napproach. There are no the sharp changing of femtoscopic parameter values, in\nparticular, $R_{o}/R_{s}$ with increasing of $\\sqrt{s_{NN}}$ which were\npredicted by some phenomenological models as signature of first order phase\ntransition in strongly interacting matter. The generalized parameterization for\nfemtoscopic correlation function is suggested.", + "category": "nucl-ex" + }, + { + "text": "Radio Frequency Phototube, Optical Clock and Precise Measurements in\n Nuclear Physics: Recently a new experimental program of novel systematic studies of light\nhypernuclei using pionic decay was established at JLab (Study of Light\nHypernuclei by Pionic Decay at JLab, JLab Experiment PR-08-012). The highlights\nof the proposed program include high precision measurements of binding energies\nof hypernuclei by using a high resolution pion spectrometer, HpiS. The average\nvalues of binding energies will be determined within an accuracy of ~10 keV or\nbetter. Therefore, the crucial point of this program is an absolute calibration\nof the HpiS with accuracy 10E-4 or better. The merging of continuous wave\nlaser-based precision optical-frequency metrology with mode-locked ultrafast\nlasers has led to precision control of the visible frequency spectrum produced\nby mode-locked lasers. Such a phase-controlled mode-locked laser forms the\nfoundation of an optical clock or femtosecond optical frequency comb (OFC)\ngenerator, with a regular comb of sharp lines with well defined frequencies.\nCombination of this technique with a recently developed radio frequency (RF)\nphototube results in a new tool for precision time measurement. We are\nproposing a new time-of-flight (TOF) system based on an RF phototube and OFC\ntechnique. The proposed TOF system achieves 10 fs instability level and opens\nnew possibilities for precise measurements in nuclear physics such as an\nabsolute calibration of magnetic spectrometers within accuracy 10E-4 - 10E-5.", + "category": "nucl-ex" + }, + { + "text": "A New Approach to Determine Radiative Capture Reaction Rates at\n Astrophysical Energies: Radiative capture reactions play a crucial role in stellar nucleosynthesis\nbut have proved challenging to determine experimentally. In particular, the\nlarge uncertainty ($\\sim$100%) in the measured rate of the\n$^{12}$C$(\\alpha,\\gamma)^{16}$O reaction is the largest source of uncertainty\nin any stellar evolution model. With development of new high current\nenergy-recovery linear accelerators (ERLs) and high density gas targets,\nmeasurement of the $^{16}$O$(e,e^\\prime \\alpha)^{12}$C reaction close to\nthreshold using detailed balance opens up a new approach to determine the\n$^{12}$C$(\\alpha,\\gamma)^{16}$O reaction rate with significantly increased\nprecision ($<$20%). We present the formalism to relate photo- and\nelectro-disintegration reactions and consider the design of an optimal\nexperiment to deliver increased precision. Once the new ERLs come online, an\nexperiment to validate the new approach we propose should be carried out. This\nnew approach has broad applicability to radiative capture reactions in\nastrophysics.", + "category": "nucl-ex" + }, + { + "text": "Global Observables at RHIC: Main characteristics of the charged particle dN_ch/deta and transverse energy\ndE_T/deta production measured in Heavy Ion collisions at RHIC energies are\npresented in this article. Transformation of the pseudo-rapidity shape,\nrelation to the incident energy and centrality profile are described in a\nsystematic way. Centrality profile is shown to be closely bound to the number\nof nucleons participating in the collisions, at the same time an alternative\napproach to study the centrality behavior is also discussed.", + "category": "nucl-ex" + }, + { + "text": "Evidence for a long-range component in the pion emission source in Au+Au\n collisions at sqrt(s_NN) = 200 GeV: Emission source functions are extracted from correlation functions\nconstructed from charged pions produced at mid-rapidity in Au+Au collisions at\nsqrt(s_NN)=200 GeV. The source parameters extracted from these functions at low\nk_T, give first indications of a long tail for the pion emission source. The\nsource extension cannot be explained solely by simple kinematic considerations.\nThe possible role of a halo of secondary pions from resonance emissions is\nexplored.", + "category": "nucl-ex" + }, + { + "text": "Silicon Vertex Tracker for PHENIX Upgrade at RHIC: Capabilities and\n Detector Technology: From the wealth of data obtained from the first three years of RHIC\noperation, the four RHIC experiments, BRAHMS, PHENIX, PHOBOS and STAR, have\nconcluded that a high density partonic matter is formed at central Au+Au\ncollisions at 200 GeV. The research focus now shifts from initial discovery to\na detailed exploration of partonic matter. Particles carrying heavy flavor,\ni.e. charm or beauty quarks, are powerful tool for study the properties of the\nhot and dense medium created in high-energy nuclear collisions at RHIC. At the\nrelatively low transverse momentum region, the collective motion of the heavy\nflavor will be a sensitive signal for the thermalization of light flavors. An\nupgrade of RHIC (RHIC-II) is intended for the second half of the decade, with a\nluminosity increase to about 20-40 times the design value of 8x1026 cm-2 s-1\nfor Au+Au, and 2x1032 cm-2 s-1 for polarized proton beams. The PHENIX\ncollaboration plans to upgrade its experiment to exploit with an enhanced\ndetector new physics then in reach. For this purpose, we are constructing the\nSilicon Vertex Tracker (VTX). The VTX detector will provide us the tool to\nmeasure new physics observables that are not accessible at the present RHIC or\navailable only with very limited accuracy. The VTX detector consists of four\nlayers of barrel detectors located in the region of pseudorapidity |eta| < 1.2\nand covers almost 2 azimuthal angle. The pseudorapidity is defined as eta =\n-ln[tan(/2)], where is the emission angle relative to the beam axis. In this\npaper, we will provide details of the physics capability added to PHENIX by the\nnew central silicon vertex tracker, the status of the project, including\ntechnology choices used in the design, performance of individual silicon sensor\nand silicon detector prototype.", + "category": "nucl-ex" + }, + { + "text": "Centrality Dependence of Neutral Pion Production in 158 A GeV Pb + Pb\n Collisions: The production of neutral pions in 158AGeV Pb+Pb collisions has been studied\nin the WA98 experiment at the CERN SPS. Transverse momentum spectra are studied\nfor the range 0.3 GeV/c < mT-m0 < 4.0 GeV/c. The results for central collisions\nare compared to various models. The centrality dependence of the neutral pion\nspectral shape and yield is investigated. An invariance of the spectral shape\nand a simple scaling of the yield with the number of participating nucleons is\nobserved for centralities with greater than about 30 participating nucleons\nwhich is most naturally explained by assuming an equilibrated system.", + "category": "nucl-ex" + }, + { + "text": "Percolation of Color Sources and the Shear Viscosity of the QGP in\n Central A-A Collisions at RHIC and LHC Energies: The Color String Percolation Model (CSPM) is used to determine the shear\nviscosity to entropy ratio ($\\eta/s$) of the Quark-Gluon Plasma (QGP) produced\nin Au-Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV at RHIC and Pb-Pb at\n$\\sqrt{s_{NN}}$ = 2.76 TeV at LHC. The relativistic kinetic theory relation for\n$\\eta/s$ is evaluated using CSPM values for the temperature and the mean free\npath of the QGP constituents. The experimental charged hadron transverse\nmomentum spectrum is used to determine the percolation density parameter $\\xi$\nin Au-Au collisions (STAR). For Pb-Pb at $\\sqrt{s_{NN}}$ = 2.76 TeV $\\xi$\nvalues are obtained from the extrapolation at RHIC energy. The value of\n$\\eta/s$ is 0.204$\\pm$0.020 and 0.262$\\pm$0.026 at the CSPM initial\ntemperatures of 193.6$\\pm$3 MeV (RHIC) and 262.2 $\\pm$13 MeV (LHC)\nrespectively. These values are 2.5 and 3.3 times the AdS/CFT conjectured lower\nbound $1/4\\pi$. We compare the CSPM $\\eta/s$ analytic expression with weak\ncoupling (wQGP) and strong coupling (sQGP) calculations. This indicates that\nthe QGP is a strongly coupled fluid in the phase transition region.", + "category": "nucl-ex" + }, + { + "text": "Neutron Interactions as Seen by A Segmented Germanium Detector: The GERmanium Detector Array, GERDA, is designed for the search for\n``neutrinoless double beta decay'' (0-nu-2-beta) with germanium detectors\nenriched in Ge76. An 18-fold segmented prototype detector for GERDA Phase II\nwas exposed to an AmBe neutron source to improve the understanding of neutron\ninduced backgrounds. Neutron interactions with the germanium isotopes\nthemselves and in the surrounding materials were studied. Segment information\nis used to identify neutron induced peaks in the recorded energy spectra. The\nGeant4 based simulation package MaGe is used to simulate the experiment. Though\nmany photon peaks from germanium isotopes excited by neutrons are correctly\ndescribed by Geant4, some physics processes were identified as being\nincorrectly treated or even missing.", + "category": "nucl-ex" + }, + { + "text": "Final State Interaction Effects in pol 3He(pol e,e'p): Asymmetries in quasi-elastic pol 3He(pol e,e'p) have been measured at a\nmomentum transfer of 0.67 (GeV/c)^2 and are compared to a calculation which\ntakes into account relativistic kinematics in the final state and a\nrelativistic one-body current operator. With an exact solution of the Faddeev\nequation for the 3He-ground state and an approximate treatment of final state\ninteractions in the continuum good agreement is found with the experimental\ndata.", + "category": "nucl-ex" + }, + { + "text": "Anisotropic flow of charged hadrons, pions and (anti-)protons measured\n at high transverse momentum in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}=2.76$\n TeV: The elliptic, $v_2$, triangular, $v_3$, and quadrangular, $v_4$, azimuthal\nanisotropic flow coefficients are measured for unidentified charged particles,\npions and (anti-)protons in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}} = 2.76$ TeV\nwith the ALICE detector at the Large Hadron Collider. Results obtained with the\nevent plane and four-particle cumulant methods are reported for the\npseudo-rapidity range $|\\eta|<0.8$ at different collision centralities and as a\nfunction of transverse momentum, $p_{\\rm T}$, out to $p_{\\rm T}=20$ GeV/$c$.\nThe observed non-zero elliptic and triangular flow depends only weakly on\ntransverse momentum for $p_{\\rm T}>8$ GeV/$c$. The small $p_{\\rm T}$ dependence\nof the difference between elliptic flow results obtained from the event plane\nand four-particle cumulant methods suggests a common origin of flow\nfluctuations up to $p_{\\rm T}=8$ GeV/$c$. The magnitude of the (anti-)proton\nelliptic and triangular flow is larger than that of pions out to at least\n$p_{\\rm T}=8$ GeV/$c$ indicating that the particle type dependence persists out\nto high $p_{\\rm T}$.", + "category": "nucl-ex" + }, + { + "text": "Photoproduction in Ultra-Peripheral Relativistic Heavy Ion Collisions\n with STAR: We present a summary of recent photoproduction results in ultra peripheral\nrelativistic heavy ions collisions with STAR. These collisions have impact\nparameters larger then twice the nuclear radius; the nuclei do not physically\ncollide, but interact via long-range electromagnetic fields. We observe\nexclusive $\\rho^0$ production as well as $AuAu\\to Au^*Au^* \\rho^0$ with\naccompanying mutual nuclear excitation at $\\sqrt{s_{NN}}=200$ GeV. We report\nthe $\\rho^0$ production cross section for both coherent and incoherent coupling\naccompanied by mutual nuclear excitation. We have studied the cross section as\na function of $p_T$, $y_{\\rho^0}$ and $M_{\\pi\\pi}$ and compared it to\ntheoretical models. In addition, we measured the $\\rho^0$ helicity matrix\nelements. They are found to be consistent with s-channel helicity conservation.\nThe ratio of coherent $\\rho^0$ and direct $\\pi^+\\pi^-$ pair photoproduction has\nbeen measured and found to be consistent with earlier measurements. The 4-pion\nfinal state $AuAu \\to \\pi^+\\pi^-\\pi^+\\pi^-$ state has also been observed.", + "category": "nucl-ex" + }, + { + "text": "STAR Overview of Hard Probe Observables: Parton energy loss, quarkonium sequential melting and particle production\nfrom electromagnetic interactions are tools to study Quark Gluon Plasma\nproperties. The STAR detector, with large acceptance at mid-rapidity, excellent\nparticle identification and wide transverse momentum coverage, is able to study\nthese probes in details. In Hard Probes 2015, the STAR collaboration reported\nmeasurements of reconstructed jets, heavy-flavor physics, di-lepton production\nand the performance of new detectors in seven presentations and one poster.\nGiven the rich results from STAR, this overview report will focus on a few\nselected results on jets and $\\Upsilon$ measurements in Au+Au collisions at\n$\\sqrt{s_{\\rm NN}}=200\\,$GeV, $J/\\psi$ production in $p$+$p$ collisions at\n$\\sqrt{s_{\\rm NN}}=500\\,$GeV, and the di-electron spectrum in the low mass\nregion from the Beam Energy Scan - Phase I.", + "category": "nucl-ex" + }, + { + "text": "High precision measurement of the $^6$He half-life: The half-life of $^{6}$He has been measured using a low energy radioactive\nbeam implanted in a YAP scintillator and recording decay events in a 4$\\pi$\ngeometry. Events were time-stamped with a digital data acquisition system\nenabling a reliable control of dead-time effects and detector gain variations.\nThe result, $T_{1/2} = (807.25 \\pm 0.16_{\\rm stat} \\pm 0.11_{\\rm sys}$)~ms,\nprovides the most precise value obtained so far and is consistent with the only\nprevious measurement having a precision smaller than 0.1%. This resolves the\nlongstanding discrepancy previously observed between two sets of measurements.", + "category": "nucl-ex" + }, + { + "text": "IUPAP Report 41 Introduction: IUPAP Report 41 is a document that gives summary information about the major\nnuclear physics facilities around the world. It is updated approximately every\nfive years by Working Group 9 of the International Union of Pure and Applied\nPhysics. The introduction to the report gives an overview of the field of\nnuclear physics and outlines the major questions facing the field. This most\nrecent version of Report 41 has been updated to reflect the state of the field\nin 2018. The full report can be found at\nhttp://www.triumf.info/hosted/iupap/icnp/report41.html", + "category": "nucl-ex" + }, + { + "text": "Experimental Results on p(d)+A Collisions at RHIC and the LHC: Recent experimental results at both the LHC and RHIC show evidence for\nhydrodynamic behavior in proton-nucleus and deuteron- nucleus collisions (p+A).\nThis unexpected finding has prompted new measurements in p+A collisions in\norder to understand whether similar matter is created in A+A and p+A collisions\nor whether some another explanation is needed. In this proceedings, we will\ndiscuss the new experimental data and its interpretation within the context of\nheavy ion collisions.", + "category": "nucl-ex" + }, + { + "text": "Final Results of the GEp-III Experiment and the Status of the Proton\n Form Factors: The recently published final results of experiment E04-108 in Jefferson Lab\nHall C extend the recoil polarization measurements of the ratio of the proton\nelectric and magnetic form factors to $Q^2 = 8.5$ GeV$^2$, an increase in $Q^2$\ncoverage of more than 50\\%. A global fit of $G_E^p$ and $G_M^p$ to selected\ndata for electron-proton elastic scattering cross sections and polarization\nobservables is presented, illustrating the statistical impact of the new\nresults.", + "category": "nucl-ex" + }, + { + "text": "High-Precision Measurement of the 19Ne Half-Life and Implications for\n Right-Handed Weak Currents: We report a precise determination of the 19Ne half-life to be $T_{1/2} =\n17.262 \\pm 0.007$ s. This result disagrees with the most recent precision\nmeasurements and is important for placing bounds on predicted right-handed\ninteractions that are absent in the current Standard Model. We are able to\nidentify and disentangle two competing systematic effects that influence the\naccuracy of such measurements. Our findings prompt a reassessment of results\nfrom previous high-precision lifetime measurements that used similar equipment\nand methods.", + "category": "nucl-ex" + }, + { + "text": "Ionoacoustic detection of swift heavy ions: The maximum energy loss (Bragg peak) located near the end of range is a\ncharacteristic feature of ion stopping in matter, which generates an acoustic\npulse, if ions are deposited into a medium in adequately short bunches. This\nso-called ionoacoustic effect has been studied for decades, mainly for\nastrophysical applications, and it has recently found renewed interest in\nproton therapy for precise range measurements in tissue. After detailed\npreparatory studies with 20 MeV protons at the MLL tandem accelerator,\nionoacoustic range measurements were performed in water at the upgraded SIS18\nsynchrotron of GSI with 238U and 124Xe ion beams of energy about 300 MeV/u, and\n12C ions of energy about 200 MeV/u using fast beam extraction to get 1\nmicrosecond pulse lengths. Acoustic signals were recorded in axial geometry by\nstandard piezo-based transducers at a 500 kHz mean frequency and evaluated in\nboth the time and frequency domains. The resulting ranges for the different\nions and energies were found to agree with Geant4 simulations as well as\nprevious measurements to better than 1%. Given the high accuracy provided by\nionoacoustic range measurements in water and their relative simplicity, we\npropose this new method for stopping power measurements for heavy ions at GeV\nenergies and above. Our experimental results clearly demonstrate the potential\nof an ionoacoustic particle monitor especially for very intense heavy ion beams\nforeseen at future accelerator facilities.", + "category": "nucl-ex" + }, + { + "text": "Accelerated electron thermometer: observation of 1D Planck radiation: We report on the observation of thermal photons from an accelerated electron\nvia examination of radiative beta decay of free neutrons measured by the RDK II\ncollaboration. The emitted photon spectrum is shown to corroborate a thermal\ndistribution consistent with the dynamical Casimir effect. Supported by a\nrobust chi-squared statistic, we find the photons reside in a one-dimensional\nPlanck spectrum with a temperature predicted by the moving mirror model.", + "category": "nucl-ex" + }, + { + "text": "Study of Azimuthal Correlations in the Target Fragmentation Region in p,\n d, He, C+C, Ta and C+Ne, Cu Collisions at a Momentum of 4.2, 4.5 and 10\n AGeV/c: Azimuthal correlations between the same type of particles (protons or pions)\nin the target fragmentation region was studied in d, He, C + C, Ta (4.2\nAGeV/c), C + Ne, Cu (4.5AGeV/c) and p + C, Ta (10 GeV/c) interactions. The data\nwere obtained from the SKM-200-GIBS streamer chamber and from Propane Bubble\nChamber (PBL-500) systems utilized at JINR. Study of multiparticle azimuthal\ncorrelations offers unique information about space-time evolution of the\ninteractions. Azimuthal correlations were investigated by using correlation\nfunction C($\\Delta\\phi$)=dN/d($\\Delta\\phi$), where $\\Delta\\phi$ represents the\nangle between the sums of transverse momenta vectors for particles emitted in\nthe forward and backward hemispheres. For protons a \"back-to back\" (\"negative\")\nazimuthal correlations were observed in the above mentioned interactions. The\nabsolute values of the correlation coefficient $|\\xi|$ -- the slope parameter\nof C($\\Delta\\phi$), strongly depend on the mass number of the target ($A_T$)\nnuclei in the nucleon-nucleus and nucleus-nucleus collisions. Namely, $|\\xi|$\n-- decreases with increase of $A_T$ in p+C and p+Ta collisions, while $|\\xi|$\ndecreases from d+C up to C+Ne and then almost does not change with increase of\n$A_P$, $A_T$ in (d+He)Ta, C+Cu and C+Ta collisions. For pions a \"back-to-back\"\ncorrelations were obtained for a light targets (C, Ne), and a \"side-by-side\"\n(\"positive\") correlations for a heavy targets (Cu, Ta). The $|\\xi|$\ninsignificantly changes with increase of the momenta per nucleon and almost\ndoes not change with increase of $A_P$ and $A_T$. Models, used for description\nof the data -- the Ultra relativistic Quantum Molecular Dynamic (UrQMD) and\nQuark-Gluon String Model (QGSM), satisfactorily describe the obtained\nexperimental results.", + "category": "nucl-ex" + }, + { + "text": "Level density of 2+ states in 40Ca from high energy-resolution (p,p')\n experiments: The level density of 2+ states in 40Ca has been extracted in the energy\nregion of the isoscalar giant quadrupole resonance (ISGQR) from a fluctuation\nanalysis of high energy-resolution p,p') data taken at incident energies of 200\nMeV at the K600 magnetic spectrometer of iThemba LABS, South Africa. Quasi-free\nscattering cross sections were calculated to estimate their role as a\nbackground contribution to the spectra and found to be small. The shape of the\nbackground was determined from the discrete wavelet transform of the spectra\nusing a biorthogonal wavelet function normalized at the lowest particle\nseparation threshold. The experimental results are compared to widely used\nphenomenological and microscopic models.", + "category": "nucl-ex" + }, + { + "text": "(Anti)nucleosynthesis in heavy-ion collisions and (anti)nuclei as\n \"baryonmeter\" of the collision: The production mechanism of light (anti)nuclei in heavy-ion collisions has\nbeen extensively studied experimentally and theoretically. Two competing\n(anti)nucleosynthesis models are typically used to describe light (anti)nuclei\nyields and their ratios to other hadrons in heavy-ion collisions: the\nstatistical hadronization model (SHM) and the nucleon coalescence model. The\npossibility to distinguish these phenomenological models calls for new\nexperimental observables. Given their large baryon number, light (anti)nuclei\nhave a high sensitivity to the baryon chemical potential ($\\mu_{\\rm B}$) of the\nsystem created in the collision. In this talk, the first measurement of\nevent-by-event antideuteron number fluctuations in heavy-ion collisions is\npresented and compared with expectations of the SHM and coalescence model. In\naddition, the antinuclei-to-nuclei ratios are used to obtain a measurement of\n$\\mu_{\\rm B}$ in heavy-ion collisions with unprecedented precision.", + "category": "nucl-ex" + }, + { + "text": "Study of the N=50 major shell effect close to $^{78}$Ni : First evidence\n of a weak coupling structure in $^{83}\\_{32}$Ge$\\_{51}$ and three-proton\n configuration states in $^{81}\\_{31}$Ga$\\_{50}$: New levels were attributed to $^{81}\\_{31}$Ga$\\_{50}$ and\n$^{83}\\_{32}$Ge$\\_{51}$ which were fed by the $\\beta$-decay of their respective\nmother nuclei $^{81}\\_{30}$Zn$\\_{51}$ and $^{83}\\_{31}$Ga$\\_{52}$ produced by\nfission at the \"PARRNe\" ISOL set-up installed at the Tandem accelerator of the\nInstitut de Physique Nucl\\'eaire, Orsay. We show that the low energy structure\nof $^{81}\\_{31}$Ga$\\_{50}$ and $^{83}\\_{32}$Ge$\\_{51}$ can easily be explained\nwithin the natural hypothesis of a strong energy gap at N=50 and a doubly-magic\ncharacter for $^{78}$Ni.", + "category": "nucl-ex" + }, + { + "text": "Coherent rho^0 Production in Ultra-Peripheral Heavy Ion Collisions: The STAR collaboration reports the first observation of exclusive rho^0\nphoto-production, AuAu->AuAu rho^0, and rho^0 production accompanied by mutual\nnuclear Coulomb excitation, AuAu->Au*Au*rho^0, in ultra-peripheral heavy-ion\ncollisions. The rho^0 have low transverse momenta, consistent with coherent\ncoupling to both nuclei. The cross sections at sqrt(s_NN)=130GeV agree with\ntheoretical predictions treating rho^0 production and Coulomb excitation as\nindependent processes.", + "category": "nucl-ex" + }, + { + "text": "Strangelet Searches in High Energy Heavy Ion Collisions: In this contribution I concentrate on the recent results from experiment E864\nat the BNL-AGS. E864's recent analysis have achieved sensitivities of\napproximately $3\\times 10^{-8}$ per 10% central interaction for the production\nof charged strangelets and the first analysis for neutral strangelets is near\ncompletion. I put the results in the context of coalescence and quark gluon\nplasma strangelet production models.", + "category": "nucl-ex" + }, + { + "text": "Emerging collectivity from the nuclear structure of $^{132}$Xe:\n Inelastic neutron scattering studies and shell-model calculations: Inelastic neutron scattering was used to study the low-lying nuclear\nstructure of $^{132}$Xe. A comprehensive level scheme is presented, as well as\nnew level lifetimes, multipole mixing ratios, branching ratios, and transition\nprobabilities. Comparisons of these data as well as previously measured $E2$\nstrengths and $g$ factors are made with new shell-model calculations for\n$^{132,134,136}$Xe to explore the emergence of collectivity in the Xe isotopes\nwith $N$ < 82 near the closed shell.", + "category": "nucl-ex" + }, + { + "text": "Measurement of electrons from heavy-flavour decays in pp and Pb-Pb\n collisions with ALICE at the LHC: The ALICE experiment has measured at mid-rapidity electrons from\nheavy-flavour decays in pp collisions at $\\sqrt{s}$ = 2.76 and 7 TeV, and in\nPb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV. In pp collisions, electrons\nfrom charm-hadron and from beauty-hadron decays are identified by applying cuts\non displaced vertices. The relative yield of electrons from beauty-hadron\ndecays to those from heavy-flavour decays is extracted using electron-hadron\ncorrelations. Results are compared to pQCD-based calculations. In Pb-Pb\ncollisions, the $p_{\\rm T}$ dependence of the nuclear modification factor of\nelectrons from heavy-flavour decays is presented in two centrality classes. The\nstatus on the analysis of electrons from beauty-hadron decays is reported in\nPb-Pb collisions, in view of the measurement of the corresponding nuclear\nmodification factor.", + "category": "nucl-ex" + }, + { + "text": "\u03c0N and \u03b7p deexcitation channels of the N^* and \u0394baryonic\n resonances between 1470 and 1680 MeV: Two reactions, pp->ppX and pp->p\\pi^+X, are used to study the 1.47}$ as a sensitive measure\nof potential changes in these azimuthal correlations. Contributions from\ntransverse radial flow are estimated.", + "category": "nucl-ex" + }, + { + "text": "Half-life measurement of 66Ga with gamma-spectroscopy: The half-life of 66Ga, an isotope very important for high-energy efficiency\ncalibration of gamma-detectors, has been measured using gamma-spectroscopy. In\norder to reduce systematic uncertainties, different source production methods\nand gamma-counting conditions have been applied. A half-life value of 9.312 +-\n0.032 h has been obtained in agreement with a recent measurement but in\ncontradiction with some of the earlier results.", + "category": "nucl-ex" + }, + { + "text": "New Constraint on the Local Relic Neutrino Background Overdensity with\n the First KATRIN Data Runs: We report on the direct cosmic relic neutrino background search from the\nfirst two science runs of the KATRIN experiment in 2019. Beta-decay electrons\nfrom a high-purity molecular tritium gas source are analyzed by a\nhigh-resolution MAC-E filter around the kinematic endpoint at 18.57 keV. The\nanalysis is sensitive to a local relic neutrino overdensity of 9.7e10 (1.1e11)\nat a 90% (95%) confidence level. A fit of the integrated electron spectrum over\na narrow interval around the kinematic endpoint accounting for relic neutrino\ncaptures in the Tritium source reveals no significant overdensity. This work\nimproves the results obtained by the previous kinematic neutrino mass\nexperiments at Los Alamos and Troitsk. We furthermore update the projected\nfinal sensitivity of the KATRIN experiment to <1e10 at 90% confidence level, by\nrelying on updated operational conditions.", + "category": "nucl-ex" + }, + { + "text": "Final Measurement of the U235 Antineutrino Energy Spectrum with the\n PROSPECT-I Detector at HFIR: This Letter reports one of the most precise measurements to date of the\nantineutrino spectrum from a purely U235-fueled reactor, made with the final\ndataset from the PROSPECT-I detector at the High Flux Isotope Reactor. By\nextracting information from previously unused detector segments, this analysis\neffectively doubles the statistics of the previous PROSPECT measurement. The\nreconstructed energy spectrum is unfolded into antineutrino energy and compared\nwith both the Huber-Mueller model and a spectrum from a commercial reactor\nburning multiple fuel isotopes. A local excess over the model is observed in\nthe 5MeV to 7MeV energy region. Comparison of the PROSPECT results with those\nfrom commercial reactors provides new constraints on the origin of this excess,\ndisfavoring at 2.2 and 3.2 standard deviations the hypotheses that\nantineutrinos from U235 are solely responsible and non-contributors to the\nexcess observed at commercial reactors respectively.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal asymmetry of direct photons in intermediate energy heavy-ion\n collisions: Hard photon emitted from energetic heavy ion collisions is of very\ninteresting since it does not experience the late-stage nuclear interaction,\ntherefore it is useful to explore the early-stage information of matter phase.\nIn this work, we have presented a first calculation of azimuthal asymmetry,\ncharacterized by directed transverse flow parameter $F$ and elliptic asymmetry\ncoefficient $v_2$, for proton-neutron bremsstrahlung hard photons in\nintermediate energy heavy-ion collisions. The positive $F$ and negative $v_2$\nof direct photons are illustrated and they seem to be anti-correlated to the\ncorresponding free proton's flow.", + "category": "nucl-ex" + }, + { + "text": "Directed Flow in 158 A GeV Pb + Pb Collisions: The directed flow of protons and positive pions have been studied in 158 A\nGeV Pb + Pb collisions. A directed flow analysis of the rapidity dependence of\nthe average transverse momentum projected onto the reaction plane is presented\nfor semi-central collisions with impact parameters of approximately 8 fm, where\nthe flow effect is largest. The magnitude of the directed flow is found to be\nsignificantly smaller than observed at AGS energies and than RQMD model\npredictions.", + "category": "nucl-ex" + }, + { + "text": "On the rearrangement time of the fission reaction: The rearrangement time \\Deltat of the fission reaction can be extracted from\nthe full-width at half maximum (f.w.h.m.) of the isotopic distributions of\nfission fragments if this width is attributed to an uncertainty \\DeltaN in the\nneutron-number N of the fragment; then the energy-time uncertainty relation\nleads to \\Deltat = 0.17 yoctosecond.", + "category": "nucl-ex" + }, + { + "text": "Experimental study of the $^{17}$F+ $^{12}$C fusion reaction and its\n implications for fusion of proton-halo systems: The halo nature of the low-lying $1/2$+ first excited state of the exotic\nweakly-bound proton drip-line nucleus $^{17}$F has long been hypothesized. The\nstructure of such a halo nucleus would imply special nuclear properties\nincluding, possibly, an enhancement in its fusion cross section above the\nbarrier. The total fusion cross section of $^{17}$F + $^{12}$C near the Coulomb\nbarrier was studied using the newly developed \"Encore\" active-target detector\nat Florida State University. Total fusion cross sections for the stable\ncounterpart systems $^{16}$O + $^{12}$C and $^{19}$F + $^{12}$C were also\nmeasured to enable a systematic comparison. No influence of the halo nature of\nthe $^{17}$F $1/2$+ first excited state on its fusion excitation function was\nobserved when compared with the stable counterpart systems.", + "category": "nucl-ex" + }, + { + "text": "Single Spin Asymmetries of Inclusive Hadrons Produced in Electron\n Scattering from a Transversely Polarized $^3$He Target: We report the first measurement of target single-spin asymmetries (A$_N$) in\nthe inclusive hadron production reaction,\n$e~$+$~^3\\text{He}^{\\uparrow}\\rightarrow h+X$, using a transversely polarized\n$^3$He target. The experiment was conducted at Jefferson Lab in Hall A using a\n5.9-GeV electron beam. Three types of hadrons ($\\pi^{\\pm}$, $\\text{K}^{\\pm}$\nand proton) were detected in the transverse hadron momentum range 0.54 $700$ MeV/c.", + "category": "nucl-ex" + }, + { + "text": "Strange Particle Production from SIS to LHC: >1A review of meson emission in heavy ion collisions at incident energies\nfrom SIS up to collider energies is presented. A statistical model assuming\nchemical equilibrium and local strangeness conservation (i.e. strangeness\nconservation per collision) explains most of the observed features.\n Emphasis is put onto the study of $K^+$ and $K^-$ emission at low incident\nenergies. In the framework of this statistical model it is shown that the\nexperimentally observed equality of $K^+$ and $K^-$ rates at\n``threshold-corrected'' energies $\\sqrt{s} - \\sqrt{s_{th}}$ is due to a\ncrossing of two excitation functions. Furthermore, the independence of the\n$K^+$ to $K^-$ ratio on the number of participating nucleons observed between\nSIS and RHIC is consistent with this model.\n It is demonstrated that the $K^-$ production at SIS energies occurs\npredominantly via strangeness exchange and this channel is approaching chemical\nequilibrium. The observed maximum in the $K^+/\\pi^+$ excitation function is\nalso seen in the ratio of strange to non-strange particle production. The\nappearance of this maximum around 30 $A\\cdot$GeV is due to the energy\ndependence of the chemical freeze-out parameters $T$ and $\\mu_B$.", + "category": "nucl-ex" + }, + { + "text": "First direct search for $2\u03b5$ and $\u03b5\u03b2^+$ decay of\n $^{144}$Sm and $2\u03b2^-$ decay of $^{154}$Sm: The first direct search for the double electron capture ($2\\epsilon$) and the\nelectron capture with positron emission ($\\epsilon\\beta^+$) in $^{144}$Sm to\nthe ground state and to the excited levels of $^{144}$Nd was realized by\nmeasuring - over 1899 h - a 342 g sample of highly purified samarium oxide\n(Sm$_2$O$_3$) with the ultra-low background HP-Ge $\\gamma$ spectrometer GeCris\n(465 cm$^3$) at the STELLA facility of the Gran Sasso National Laboratory\n(LNGS). No effect was observed and half-life limits were estimated at the level\nof $T_{1/2} \\sim (0.1-1.3) \\times 10^{20}$ yr (90% C.L.). Moreover, for the\nfirst time half-life limits of the double beta ($2\\beta^-$) decay of $^{154}$Sm\nto several excited levels of $^{154}$Gd have been set; they are at the level of\n$T_{1/2} \\sim (0.06-8) \\times 10^{20}$ yr (90% C.L.).", + "category": "nucl-ex" + }, + { + "text": "Experimental results on charge fluctuations in heavy-ion collisions: We present a subset of experimental results on charge fluctuation from the\nheavy-ion collisions to search for phase transition and location of critical\npoint in the QCD phase diagram. Measurements from the heavy-ion experiments at\nthe SPS and RHIC energies observe that total charge fluctuations increase from\ncentral to peripheral collisions. The net-charge fluctuations in terms of\ndynamical fluctuation measure $\\nu_{(+-,dyn)}$ are studied as a function of\ncollision energy (\\sqsn) and centrality of the collisions. The product of\n$\\nu_{(+-,dyn)}$ and $\\langle N_{ch} \\rangle$ shows a monotonic decrease with\ncollision energies, which indicates that at LHC energy the fluctuations have\ntheir origin in the QGP phase. The fluctuations in terms of higher moments of\nnet-proton, net-electric charge and net-kaon have been measured for various\n\\sqsn. Deviations are observed in both $S\\sigma$ and $\\kappa\\sigma^2$ for\nnet-proton multiplicity distributions from the Skellam and hadron resonance gas\nmodel for \\sqsn $<$ 39 GeV. Higher moment results of the net-electric charge\nand net-kaon do not observe any significant non-monotonic behavior as a\nfunction of collision energy. We also discuss the extraction of the freeze-out\nparameters using particle ratios and experimentally measured higher moments of\nnet-charge fluctuations. The extracted freeze-out parameters from\nexperimentally measured moments and lattice calculations, are found to be in\nagreement with the results obtained from the fit of particle ratios to the\nthermal model calculations.", + "category": "nucl-ex" + }, + { + "text": "Search for the critical point of strongly interacting matter in NA49: Theoretical calculations locate the QCD critical point at energies accessible\nat the CERN SPS. Several observables were suggested to look for it. Here, we\npresent the system size dependence and the energy dependence of event-by-event\nmean transverse momentum and multiplicity fluctuations, as well as the energy\ndependence of anti-baryon to baryon ratios.", + "category": "nucl-ex" + }, + { + "text": "Could the GSI Oscillations be Observed in a Standard Electron Capture\n Decay Experiment?: The electron-capture decay of 180Re has been investigated to search for\noscillations in the decay probability as reported from a recent measurement at\nGSI, Darmstadt. The production period was kept short compared to the reported\noscillation period. No such oscillation was observed, indicating that the\nreported oscillations would not have been observable in a conventional\nexperiment with radioactive atoms in a solid environment but must have to do\nwith the unique conditions in the GSI experiment where hydrogen-like ions are\nmoving independently in a storage ring and decaying directly by a true two-body\ndecay to a long-lived (ground-) state. Our finding could restrict possible\ntheoretical interpretations of the oscillations.", + "category": "nucl-ex" + }, + { + "text": "Centrality Dependence of Particle Production in p-A collisions measured\n by ALICE: We present the centrality dependence of particle production in p-Pb\ncollisions at sqrt(s_NN)= 5.02 TeV measured by the ALICE experiment, including\nthe pseudo-rapidity and transverse momentum spectra, with a special emphasis on\nthe event classification in centrality classes and its implications for the\ninterpretation of the nuclear effects.", + "category": "nucl-ex" + }, + { + "text": "Nuclear deformation and neutron excess as competing effects for pygmy\n dipole strength: The electromagnetic dipole strength below the neutron-separation energy has\nbeen studied for the xenon isotopes with mass numbers A = 124, 128, 132, and\n134 in nuclear resonance fluorescence experiments using the ELBE bremsstrahlung\nfacility at Helmholtz-Zentrum Dresden-Rossendorf and the HIgS facility at\nTriangle Universities Nuclear Laboratory Durham. The systematic study gained\nnew information about the influence of the neutron excess as well as of nuclear\ndeformation on the strength in the region of the pygmy dipole resonance. The\nresults are compared with those obtained for the chain of molybdenum isotopes\nand with predictions of a random-phase approximation in a deformed basis. It\nturned out that the effect of nuclear deformation plays a minor role compared\nwith the one caused by neutron excess. A global parametrization of the strength\nin terms of neutron and proton numbers allowed us to derive a formula capable\nof predicting the summed E1 strengths in the pygmy region for a wide mass range\nof nuclides.", + "category": "nucl-ex" + }, + { + "text": "Proton charge radius from electron scattering: The rms-radius $R$ of the proton charge distribution is a fundamental\nquantity needed for precision physics. This radius, traditionally determined\nfrom elastic electron-proton scattering via the slope of the Sachs form factor\n$G_e(q^2)$ extrapolated to momentum transfer $q^2$=0, shows a large scatter. We\ndiscuss the approaches used to analyze the e-p data, partly redo these analyses\nin order to identify the sources of the discrepancies, and explore alternative\nparameterizations. The problem lies in the model dependence of the\nparameterized $G(q)$ needed for the extrapolation. This shape of $G(q\\tau_{\\rm d}>\\tau_{\\rm t}$ is evidenced via the correlation\nfunctions of nonidentical particle pairs. Assuming the similar source size, the\nsame emission order is inferred from the correlation functions of identical\nparticle pairs, where $\\tau_{\\rm p} \\approx 100 {\\rm ~fm/c}$ is extracted by\nthe fit of Koonin-Pratt equation to p-p correlation function. Transport model\nsimulations demonstrate that the dynamic emission order of light charged\nparticles depends on the stiffness of the nuclear symmetry energy.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal anisotropy of charged particles at high transverse momenta in\n PbPb collisions at sqrt(s[NN]) = 2.76 TeV: The azimuthal anisotropy of charged particles in PbPb collisions at\nnucleon-nucleon center-of-mass energy of 2.76 TeV is measured with the CMS\ndetector at the LHC over an extended transverse momentum (pt) range up to\napproximately 60 GeV. The data cover both the low-pt region associated with\nhydrodynamic flow phenomena and the high-pt region where the anisotropies may\nreflect the path-length dependence of parton energy loss in the created medium.\nThe anisotropy parameter (v2) of the particles is extracted by correlating\ncharged tracks with respect to the event-plane reconstructed by using the\nenergy deposited in forward-angle calorimeters. For the six bins of collision\ncentrality studied, spanning the range of 0-60% most-central events, the\nobserved v2 values are found to first increase with pt, reaching a maximum\naround pt = 3 GeV, and then to gradually decrease to almost zero, with the\ndecline persisting up to at least pt = 40 GeV over the full centrality range\nmeasured.", + "category": "nucl-ex" + }, + { + "text": "Probing the QGP with charm at ALICE-LHC: The exclusive reconstruction of D^0 mesons in the ALICE experiment allows to\nstudy the QCD energy loss of charm quarks in the deconfined quark-gluon plasma\n(QGP) medium expected to be produced in central nucleus-nucleus collisions at\nthe Large Hadron Collider.", + "category": "nucl-ex" + }, + { + "text": "Review of anisotropic flow correlations in ultrarelativistic heavy-ion\n collisions: Anisotropic flow phenomena is a key probe of the existence of Quark-Gluon\nPlasma. Several new observable associated with correlations between anisotropic\nflow harmonics are developed, which are expected to be sensitive to the initial\nfluctuations and transport properties of the created matter in heavy ion\ncollisions. I review recent developments of correlations of anisotropic flow\nharmonics. The experimental measurements, together with the comparisons to\ntheoretical model calculations, open up new opportunities of exploring novel\nQCD dynamics in heavy-ion collisions.", + "category": "nucl-ex" + }, + { + "text": "New Measurement of the Scintillation Efficiency of Low-Energy Nuclear\n Recoils in Liquid Xenon: Particle detectors that use liquid xenon (LXe) as detection medium are among\nthe leading technologies in the search for dark matter weakly interacting\nmassive particles (WIMPs). A key enabling element has been the low-energy\ndetection threshold for recoiling nuclei produced by the interaction of WIMPs\nin LXe targets. In these detectors, the nuclear recoil energy scale is based on\nthe LXe scintillation signal and thus requires knowledge of the relative\nscintillation efficiency of nuclear recoils, Leff. The uncertainty in Leff at\nlow energies is the largest systematic uncertainty in the reported results from\nLXe WIMP searches at low masses. In the context of the XENON Dark Matter\nproject, a new LXe scintillation detector has been designed and built\nspecifically for the measurement of Leff at low energies, with an emphasis on\nmaximizing the scintillation light detection efficiency to obtain the lowest\npossible energy threshold. We report new measurements of Leff at low energies\nperformed with this detector. Our results suggest a Leff which slowly decreases\nwith energy, from 0.144 +/- 0.009 at 15 keV down to 0.088 +0.014 -0.015 at 3\nkeV.", + "category": "nucl-ex" + }, + { + "text": "Collision-Induced Dissociation at TRIUMF's Ion Trap for Atomic and\n Nuclear science: The performance of high-precision mass spectrometry of radioactive isotopes\ncan often be hindered by large amounts of contamination, including molecular\nspecies, stemming from the production of the radioactive beam. In this paper,\nwe report on the development of Collision-Induced Dissociation (CID) as a means\nof background reduction for experiments at TRIUMF's Ion Trap for Atomic and\nNuclear science (TITAN). This study was conducted to characterize the quality\nand purity of radioactive ion beams and the reduction of molecular contaminants\nto allow for mass measurements of radioactive isotopes to be done further from\nnuclear stability. This is the first demonstration of CID at an ISOL-type\nradioactive ion beam facility, and it is shown that molecular contamination can\nbe reduced up to an order of magnitude.", + "category": "nucl-ex" + }, + { + "text": "Direct virtual photon production in Au+Au collisions at $\\sqrt{s_{NN}}$\n = 200 GeV: We report the direct virtual photon invariant yields in the transverse\nmomentum ranges $1\\!<\\!p_{T}\\!<\\!3$ GeV/$c$ and $5\\!<\\!p_T\\!<\\!10$ GeV/$c$ at\nmid-rapidity derived from the dielectron invariant mass continuum region\n$0.106$ GeV/$c$ the\nproduction follows $N_{bin}$ scaling. Model calculations with contributions\nfrom thermal radiation and initial hard parton scattering are consistent within\nuncertainties with the direct virtual photon invariant yield.", + "category": "nucl-ex" + }, + { + "text": "Fission Fragment Angular Anisotropy in Neutron-Induced Fission of\n $^{235}$U Measured with a Time Projection Chamber: Fission fragment angular distributions can provide an important constraint on\nfission theory, improving predictive fission codes, and are a prerequisite for\na precise ratio cross section measurement. Available anisotropy data is sparse,\nespecially at neutron energies above 5 MeV. For the first time, a\nthree-dimensional tracking detector is employed to study fragment emission\nangles and provide a direct measurement of angular anisotropy. The Neutron\nInduced Fission Fragment Tracking Experiment (NIFFTE) collaboration has\ndeployed the fission time projection chamber (fissionTPC) to measure nuclear\ndata with unprecedented precision. The fission fragment anisotropy of $^{235}$U\nhas been measured over a wide range of incident neutron energies from 180 keV\nto 200 MeV; a careful study of the systematic uncertainties complement the\ndata.", + "category": "nucl-ex" + }, + { + "text": "Production of phi mesons at mid-rapidity in sqrt(s_NN) = 200 GeV Au+Au\n collisions at RHIC: We present the first results of meson production in the K^+K^- decay channel\nfrom Au+Au collisions at sqrt(s_NN) = 200 GeV as measured at mid-rapidity by\nthe PHENIX detector at RHIC. Precision resonance centroid and width values are\nextracted as a function of collision centrality. No significant variation from\nthe PDG accepted values is observed. The transverse mass spectra are fitted\nwith a linear exponential function for which the derived inverse slope\nparameter is seen to be constant as a function of centrality. These data are\nalso fitted by a hydrodynamic model with the result that the freeze-out\ntemperature and the expansion velocity values are consistent with the values\npreviously derived from fitting single hadron inclusive data. As a function of\ntransverse momentum the collisions scaled peripheral.to.central yield ratio RCP\nfor the is comparable to that of pions rather than that of protons. This result\nlends support to theoretical models which distinguish between baryons and\nmesons instead of particle mass for explaining the anomalous proton yield.", + "category": "nucl-ex" + }, + { + "text": "Mass measurement of 56Sc reveals a small A=56 odd-even mass staggering,\n implying a cooler accreted neutron star crust: We present the mass excesses of 52-57Sc, obtained from recent time-of-flight\nnuclear mass measurements at the National Superconducting Cyclotron Laboratory\nat Michigan State University. The masses of 56Sc and 57Sc were determined for\nthe first time with atomic mass excesses of -24.85(59)(+0 -54) MeV and\n-21.0(1.3) MeV, respectively, where the asymmetric uncertainty for 56Sc was\nincluded due to possible contamination from a long-lived isomer. The 56Sc mass\nindicates a small odd-even mass staggering in the A = 56 mass-chain towards the\nneutron drip line, significantly deviating from trends predicted by the global\nFRDM mass model and favoring trends predicted by the UNEDF0 and UNEDF1 density\nfunctional calculations. Together with new shell-model calculations of the\nelectron-capture strength function of 56Sc, our results strongly reduce\nuncertainties in model calculations of the heating and cooling at the 56Ti\nelectron-capture layer in the outer crust of accreting neutron stars. We found\nthat, in contrast to previous studies, neither strong neutrino cooling nor\nstrong heating occurs in this layer. We conclude that Urca cooling in the outer\ncrusts of accreting neutron stars that exhibit superbursts or high temperature\nsteady-state burning, which are predicted to be rich in A=56 nuclei, is\nconsiderably weaker than predicted. Urca cooling must instead be dominated by\nelectron capture on the small amounts of adjacent odd-A nuclei contained in the\nsuperburst and high temperature steady-state burning ashes. This may explain\nthe absence of strong crust Urca cooling inferred from the observed cooling\nlight curve of the transiently accreting x-ray source MAXI J0556-332.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the Shared Momentum Fraction $z_g$ using Jet\n Reconstruction in p+p and Au+Au Collisions with STAR: One key difference in current energy loss models lies in the treatment of the\nAltarelli-Parisi, AP, splitting functions. It has been shown that the shared\nmomentum fraction, henceforth called Jet Splitting Function $z_g$ as determined\nby the SoftDrop grooming process can be made a Sudakov-safe measurement of the\nsymmetrized AP functions in p+p collisions. The STAR collaboration presents the\nfirst $z_g$ measurements at $\\sqrt{s_{NN}}=200$ GeV in p+p and Au+Au\ncollisions, where in Au+Au we use the specific di-jet selection introduced in\nour previous momentum imbalance measurement. For a jet resolution parameter of\n$R=0.4$, these di-jet pairs were found to be significantly imbalanced with\nrespect to p+p, yet regained balance when all soft constituents were included.\nWe find that within uncertainties there are no signs of a modified Jet\nSplitting Function on trigger or recoil side of this di-jet selection.", + "category": "nucl-ex" + }, + { + "text": "Anisotropy in the pion angular distribution of the reaction pp -> pp pi0\n at 400 MeV: The reaction pp -> pp pi0 was studied with the WASA detector at the CELSIUS\nstorage ring. The center of mass angular distribution of the pi0 was obtained\nby detection of the gamma decay products together with the two outgoing\nprotons, and found to be anisotropic with a negative second derivative slope,\nin agreement with the theoretical predictions from a microscopic calculation.", + "category": "nucl-ex" + }, + { + "text": "Caloric Curves and Nuclear Expansion: Nuclear caloric curves have been analyzed using an expanding Fermi gas\nhypothesis to extract average nuclear densities. In this approach the observed\nflattening of the caloric curves reflects progressively increasing expansion\nwith increasing excitation energy. This expansion results in a corresponding\ndecrease in the density and Fermi energy of the excited system. For nuclei of\nmedium to heavy mass apparent densities ~ 0.4 rho_0 are reached at the higher\nexcitation energies.", + "category": "nucl-ex" + }, + { + "text": "HPRL -- International cooperation to identify and monitor priority\n nuclear data needs for nuclear applications: The OECD-NEA High Priority Request List (HPRL) is a point of reference to\nguide and stimulate the improvement of nuclear data for nuclear energy and\nother applications, and a tool to bridge the gap between data users and\nproducers. The HPRL is application-driven and the requests are submitted by\nnuclear data users or representatives of the user's communities. A panel of\ninternational experts reviews and monitors the requests in the framework of an\nExpert Group mandated by the NEA Nuclear Science Committee Working Party on\nInternational Nuclear Data Evaluation Cooperation (WPEC). After approval,\nindividual requests are classified to three categories: high priority requests,\ngeneral requests, and special purpose requests (e.g., dosimetry, standards).\nThe HPRL is hosted by the NEA in the form of a relational database publicly\navailable on the web. This paper provides an overview of HPRL entries, status\nand outlook. Examples of requests successfully completed are given and new\nrequests are described with emphasis on updated nuclear data needs in the\nfields of nuclear energy, neutron standards and dosimetry.", + "category": "nucl-ex" + }, + { + "text": "Creation and decay of eta-mesic nuclei: First experimental results on photoproduction of eta-mesic nuclei are\nanalyzed. In an experiment performed at the 1 GeV electron synchrotron of the\nLebedev Physical Institute, correlated pi+n pairs arising from the reaction\ngamma + 12C -> N + eta(A-1) -> N + pi+ + n + (A-2) and flying transversely to\nthe photon beam have been observed. When the photon energy exceeds the\neta-meson production threshold, a distribution of the pi+n pairs over their\ntotal energy is found to have a peak in the subthreshold region of the\ninternal-conversion process eta p -> pi+ n which signals about formation of\neta-mesic nuclei.", + "category": "nucl-ex" + }, + { + "text": "High $p_T$ Measurements from PHENIX: We present recent high transverse momentum measurements by the PHENIX\nexperiment for Au+Au and p+p collisions at $\\sqrt{s_{NN}} = 200$ GeV at the\nRelativistic Heavy Ion Collider (RHIC). We show particle spectra for neutral\npions and charged hadrons, define and show the nuclear modification factor, and\ndiscuss particle composition. By means of the nuclear modification factor, we\nobserve a suppression factor of 5-6 for neutral pions and 3-4 for charged\nhadrons in central collisions at high $p_T$. We find that the ratio of $\\pi^0$\nto $(h^++h^-)/2$ remains nearly constant at $\\sim 0.5$ for $p_T = 2-9$ GeV/c.\nFinally we present strong evidence for the observation of jets in Au+Au\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "Positrons at Jefferson Laboratory: We review the compelling case for establishing a capability to accelerate\npositrons at Jefferson Lab. The potential appplications range from the study of\ntwo-photon exchange and deeply-virtual Compton scattering to exploiting the\ncharge current weak interaction to probe the flavor structure of hadrons and\nnuclei. There are also fascinating ideas for using such a capability to\ndiscover new physics beyond the Standard Model of nuclear and particle physics.", + "category": "nucl-ex" + }, + { + "text": "Results from PHENIX at RHIC: Results from PHENIX at RHIC in p-p and Au+Au collisions are presented from\nthe perspective of measurements in p-p collisions at the CERN ISR which serve\nas a basis for many of the techniques used. Notable results include the\nequality of the suppression of inclusive pi0 and direct electrons (from the\ndecay of heavy quarks) in the range of transverse momentuum 4 < pT < 9 GeV/c in\ncentral Au+Au collisions. This result appears to strongly disfavor the\nexplanation of suppression as due to radiative energy loss of partons\ntraversing a Quark Gluon Plasma but opens up a fundamental discussion of how\nFermions get mass, whether all six quarks are nearly massless in a QGP and how\nto test this.", + "category": "nucl-ex" + }, + { + "text": "Inclusive jet spectra in 2.76 TeV collisions from ALICE: Measurements of high-pT particle production in heavy-ion collisions at RHIC\nhave shown that medium-induced energy loss affects the partons produced in the\nearly stage of a heavy-ion col- lision. The increased initial production cross\nsection for partons at LHC energies makes fully reconstructed jets available in\na wide kinematic range, which allows for a more differential in- vestigation of\nparton energy loss. Partonic energy loss allows us to access key observables of\nthe hot deconfined nuclear matter produced in heavy-ion collisions. The\ninclusive cross-section of reconstructed jets using the ALICE tracking\ndetectors and electromagnetic calorimeter is pre- sented from data collected\nduring the 2.76 TeV pp runs. The procedures used to reconstruct jets and\nextract them from a fluctuating background in Pb-Pb collisions are discussed.", + "category": "nucl-ex" + }, + { + "text": "Estimation of CP violating EDMs from known mechanisms in the SM: New sources of CP violation, beyond the known sources in the standard model\n(SM), are required to explain the baryon asymmetry of the universe. Measurement\nof a non-zero permanent electric dipole moment (EDM) for fundamental particles,\nsuch as in an electron or a neutron, or in nuclei or atoms, can help us gain a\nhandle on the sources of CP violation, both in SM and beyond. Multiple\nmechanisms within the SM can generate CP violating EDMs, viz.\\ through the CKM\nmatrix in the weak sector or through the QCD $\\bar{\\theta}$ parameter in the\nstrong sector. We will estimate the maximum possible EDMs of leptons, certain\nbaryons, select atoms and molecules in the (CKM$\\bigoplus\\bar{\\theta}$)\nframework, assuming that the EDM wholly originates from either of the two SM\nmechanisms, independently. These estimates have been presented in light of the\ncurrent experimental upper limits on the EDMs, in the following systems -\nleptons: $e^-$, $\\mu^-$, $\\tau^-$, $\\nu_e^0$, $\\nu^0_{\\mu}$, $\\nu^0_{\\tau}$,\nbaryons: $n^0$, $p^+$, $\\Lambda^0$, $\\Sigma^0$, $\\Xi^0$, $\\Lambda^+_c$,\n$\\Xi^+_c$, atoms: $^{85}$Rb, $^{133}$Cs, $^{210}$Fr, $^{205}$Tl, $^{199}$Hg,\n$^{129}$Xe, $^{225}$Ra, $^{223}$Rn, and molecules: HfF$^+$, PbO, YbF, ThO, RaF,\nTlF. Particularly, to drive home the point that EDMs in different systems\nconstrain CP-violating interactions differently, we show that the same measured\nconstraint on the EDM in two different systems may not actually be equally\nconstraining on CP violating parameters, and to emphasize the need to measure a\nnon-zero EDM in multiple systems before understanding the origins of these\nCP-violating EDMs.", + "category": "nucl-ex" + }, + { + "text": "Lambda production in central Pb+Pb collisions at CERN-SPS energies: In this paper we present recent results from the NA49 experiment for\n$\\Lambda$ and $\\bar{\\Lambda}$ hyperons produced in central Pb+Pb collisions at\n40, 80 and 158 A$\\cdot$GeV. Transverse mass spectra and rapidity distributions\nfor $\\Lambda$ are shown for all three energies. The shape of the rapidity\ndistribution becomes flatter with increasing beam energy. The multiplicities at\nmid-rapidity as well as the total yields are studied as a function of collision\nenergy including AGS measurements. The ratio $\\Lambda/\\pi$ at mid-rapidity and\nin 4$\\pi$ has a maximum around 40 A$\\cdot$GeV. In addition, $\\bar{\\Lambda}$\nrapidity distributions have been measured at 40 and 80 A$\\cdot$GeV, which\nallows to study the $\\bar{\\Lambda}$/$\\Lambda$ ratio.", + "category": "nucl-ex" + }, + { + "text": "Mass Measurement of $^{27}$P to Constrain Type-I X-ray Burst Models and\n Validate the IMME for the A=27, T=$\\frac{3}{2}$ Isospin Quartet: Light curves are the primary observable of type-I x-ray bursts. Computational\nx-ray burst models must match simulations to observed light curves. Most of the\nerror in simulated curves comes from uncertainties in $rp$ process reaction\nrates, which can be reduced via precision mass measurements of\nneutron-deficient isotopes in the $rp$ process path.\n We perform a precise Penning trap mass measurement of $^{27}$P utilizing the\nToF-ICR technique. We use this measurement to calculate $rp$ process reaction\nrates and input these rates into an x-ray burst model to reduce simulated light\ncurve uncertainty. We also use the mass measurement of $^{27}$P to validate the\nIsobaric Multiplet Mass Equation (IMME) for the A=27 T=$\\frac{3}{2}$ isospin\nquartet which $^{27}$P belongs to.\n The mass excess of $^{27}$P was measured to be -670.7(6) keV, a fourteen-fold\nprecision increase over the mass reported in the 2020 Atomic Mass Evaluation\n(AME2020). X-ray burst light curves were produced with the MESA (Modules for\nExperiments in Stellar Astrophysics) code using the new mass and associated\nreaction rates. Changes in the mass of $^{27}$P seem to have minimal effect on\nlight curves, even in burster systems tailored to maximize impact.\n The mass of $^{27}$P does not play a significant role in x-ray burst light\ncurves. It is important to understand that more advanced models do not just\nprovide more precise results, but often qualitatively different ones. This\nresult brings us a step closer to extracting stellar parameters from individual\nx-ray burst observations. The IMME has been validated for the $A=27, T=3/2$\nquartet. The normal quadratic form of the IMME using the latest data yields a\nreduced $\\chi^2$ of 2.9. The cubic term required to generate an exact fit to\nthe latest data matches theoretical attempts to predict this term.", + "category": "nucl-ex" + }, + { + "text": "Preliminary study of feasibility of an experiment looking for excited\n state double beta transitions in tin: An attempt to study the feasibility of a new experiment to search for double\nbeta decay in $^{112}$Sn and $^{124}$Sn was carried out by using ultra-low\nbackground HPGe detector (244 cm$^{3}$) inside the Gran Sasso National\nLaboratory (LNGS) of the INFN (Italy). A small sample of natural Sn was\nexamined for 2367.5 h. The radioactive contamination of the sample has been\nestimated. The data has also been considered to calculate the present\nsensitivity for the proposed search; half-life limits $\\sim$ $10^{17} -\n10^{18}$ years for $\\beta^{+}$EC and EC-EC processes in $^{112}$Sn and $\\sim$\n$10^{18}$ years for $\\beta^{-}\\beta^{-}$ transition in $^{124}$Sn were\nmeasured. In the last section of the paper the enhancement of the sensitivity\nfor a proposed experiment with larger mass to reach theoretically estimated\nvalues of half-lives is discussed.", + "category": "nucl-ex" + }, + { + "text": "Flow harmonics in heavy ion physics at CMS and ATLAS: How can we gain a detailed insight into the hydrodynamic response of the\nsystem created in heavy ion collisions to the fluctuating initial geometry and\nviscous effects? Do we create a strongly interacting medium in proton-nucleus\nand proton-proton collisions, or rather a system of partons undergoing few\nscatterings? To what extent can we discriminate between initial momentum\ncorrelations and flow generated as a response to the initial geometry via\ninteractions in the final state? Do measurements of identified particle flow\nconfirm the observations from inclusive charged hadrons? An experimental\noverview of anisotropic flow measurements, ranging from large down to the\nsmallest collision systems, is given in these proceedings.", + "category": "nucl-ex" + }, + { + "text": "Systematic Trends of 0$^+_2$, 1$^-_1$, 3$^-_1$ and 2$^+_1$ Excited\n States in Even-Even Nuclei: The spin and parity ($J^{\\pi}$) assignments in even-even nuclei were reviewed\nacross the nuclear chart using the Evaluated Nuclear Structure Data File\n(ENSDF). The prevalence of 2$^+_1$ first or lowest excited states is confirmed.\nThe properties of 0$^+_2$, 1$^-_1$, and 3$^-_1$ lowest excited states were\nreexamined using the ENSDF data evaluation procedures. The $J^{\\pi}$ systematic\ntrends and correlations between level quantum numbers and nuclear physics\nphenomena are discussed.", + "category": "nucl-ex" + }, + { + "text": "Joint Measurement of the $^{235}$U Antineutrino Spectrum by Prospect and\n Stereo: The PROSPECT and STEREO collaborations present a combined measurement of the\npure $^{235}$U antineutrino spectrum, without site specific corrections or\ndetector-dependent effects. The spectral measurements of the two highest\nprecision experiments at research reactors are found to be compatible with\n$\\chi^2/\\mathrm{ndf} = 24.1/21$, allowing a joint unfolding of the prompt\nenergy measurements into antineutrino energy. This $\\bar{\\nu}_e$ energy\nspectrum is provided to the community, and an excess of events relative to the\nHuber model is found in the 5-6 MeV region. When a Gaussian bump is fitted to\nthe excess, the data-model $\\chi^2$ value is improved, corresponding to a\n$2.4\\sigma$ significance.", + "category": "nucl-ex" + }, + { + "text": "Exploiting neutron-rich radioactive ion beams to constrain the symmetry\n energy: The Modular Neutron Array (MoNA) and 4 Tm Sweeper magnet were used to measure\nthe free neutrons and heavy charged particles from the radioactive ion beam\ninduced 32Mg + 9Be reaction. The fragmentation reaction was simulated with the\nConstrained Molecular Dynamics model(CoMD), which demonstrated that the \nof the heavy fragments and free neutron multiplicities were observables\nsensitive to the density dependence of the symmetry energy at sub-saturation\ndensities. Through comparison of these simulations with the experimental data\nconstraints on the density dependence of the symmetry energy were extracted.\nThe advantage of radioactive ion beams as a probe of the symmetry energy is\ndemonstrated through examination of CoMD calculations for stable and\nradioactive beam induced reactions.", + "category": "nucl-ex" + }, + { + "text": "Elastic Positron-Proton Scattering at Low Q$^2$: Systematic differences in the the proton's charge radius, as determined by\nordinary atoms and muonic atoms, have caused a resurgence of interest in\nelastic lepton scattering measurements. The proton's charge radius, defined as\nthe slope of the charge form factor at Q$^2$=0, does not depend on the probe.\nAny difference in the apparent size of the proton, when determined from\nordinary versus muonic hydrogen, could point to new physics or need for the\nhigher order corrections. While recent measurements seem to now be in\nagreement, there is to date no high precision elastic scattering data with both\nelectrons and positrons. A high precision proton radius measurement could be\nperformed in Hall B at Jefferson Lab with a positron beam and the calorimeter\nbased setup of the PRad experiment. This measurement could also be extended to\ndeuterons where a similar discrepancy has been observed between the muonic and\nelectronic determination of deuteron charge radius. A new, high precision\nmeasurement with positrons, when viewed alongside electron scattering\nmeasurements and the forthcoming MUSE muon scattering measurement, could help\nprovide new insights into the origins of the proton radius puzzle, and also\nprovide new experimental constraints on radiative correction calculations.", + "category": "nucl-ex" + }, + { + "text": "Double beta decay searches of Xe-134, Xe-126 and Xe-124 with large scale\n Xe detectors: The sensitivity for double beta decay studies of Xe-134 and Xe-124 is\ninvestigated assuming a potential large scale Xe experiment developed for dark\nmatter searches depleted in Xe-136. The opportunity for an observation of the\n2nu double beta decay of Xe-134 is explored for various scenarios. A positive\nobservation should be possible for all calculated nuclear matrix elements. The\ndetection of 2$\\nu$ ECEC of Xe-124 can be probed in all scenarios covering the\ntheoretical predicted half-life uncertainties and a potential search for Xe-126\nis discussed. The sensitivity to beta+/EC decay of Xe-124 is discussed and a\npositive observation might be possible, while beta+/beta+ decay still remains\nunobservable. The performed studies take into account solar pp-neutrino\ninteractions, $^{85}$Kr beta decay and remaining Xe-136 double beta decay as\nbackground components in the depleted detector.", + "category": "nucl-ex" + }, + { + "text": "The $(\u03c0^-,\u03b3\u03b3)$ program at TRIUMF: We report the first observation of the doubly-radiative decay mode of pionic\nhydrogen (pi- p --> gamma gamma n) and and deuterium (pi- d --> gamma gamma X)\nusing the RMC pair spectrometer at TRIUMF. The process is interesting in the\ncontext of the pi-Compton scattering and the chiPT predictions of the pion\npolarizability We present our preliminary values for the B.R.(pi- p --> gamma\ngamma n)=3.8x10^-5 and B.R.(pi- d --> gamma gamma X)=1.6x10^-5. Our pi- p data\nindicates the dominance of pi pi --> gamma gamma mechanism. The pi- d data\nshows no evidence for the d1* dibaryon.", + "category": "nucl-ex" + }, + { + "text": "Study of the light nuclei cluster structures in three-body\n photodisintegration reactions. Application for the excited states of 6He\n nucleus: An experimental program for the study of the cluster structures of excited\nstates for the light nuclei of He, Li and Be in three-body photodisintegration\nprocesses is proposed. The investigations will be realized with 6Li, 7Li and\n9Be targets in seven photodisintegration reactions. As an application, the\nphotodisintegration of 7Li nuclei into the (t+t+p) final state with excitation\nand decay of neutron-rich 6He nucleus into the (t+t) channel is considered. The\nfull Monte-Carlo simulation of the experiment is done with a special impact on\nthe study of experimental setup performance, concerning the photon and excited\nstates energy resolutions. The experiment will be performed on the\nbremsstrahlung photon beam of the Yerevan Electron Synchrotron.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the 33S(\u03b1,p)36Cl cross section: Implications for\n production of 36Cl in the early Solar System: Short-lived radionuclides (SLRs) with lifetimes \\tau < 100 Ma are known to\nhave been extant when the Solar System formed over 4.5 billion years ago.\nIdentifying the sources of SLRs is important for understanding the timescales\nof Solar System formation and processes that occurred early in its history.\nExtinct 36Cl (t_1/2 = 0.301 Ma) is thought to have been produced by interaction\nof solar energetic particles (SEPs), emitted by the young Sun, with gas and\ndust in the nascent Solar System. However, models that calculate SLR production\nin the early Solar System (ESS) lack experimental data for the 36Cl production\nreactions. We present here the first measurement of the cross section of one of\nthe main 36Cl production reactions, 33S(\\alpha,p)36Cl, in the energy range 0.70\n- 2.42 MeV/A. The cross section measurement was performed by bombarding a\ntarget and collecting the recoiled 36Cl atoms produced in the reaction,\nchemically processing the samples, and measuring the 36Cl/Cl ratio of the\nactivated samples with accelerator mass spectrometry (AMS). The experimental\nresults were found to be systematically higher than the cross sections used in\nprevious local irradiation models and other Hauser-Feshbach calculated\npredictions. However, the effects of the experimentally measured cross sections\non the modeled production of 36Cl in the early Solar System were found to be\nminimal. Reactions channels involving S targets dominate 36Cl production, but\nthe astrophysical event parameters can dramatically change each reactions'\nrelative contribution.", + "category": "nucl-ex" + }, + { + "text": "Quenching of Single-Particle Strength in A=15 Nuclei: Absolute cross sections for the addition of $s$- and $d$-wave neutrons to\n$^{14}$C and $^{14}$N have been determined simultaneously via the ($d$,$p$)\nreaction at 10 MeV/u. The difference between the neutron and proton separation\nenergies, $\\Delta S$, is around $-20$ MeV for the $^{14}$C$+$$n$ system and\n$+8$ MeV for $^{14}$N$+$$n$. The population of the $1s_{1/2}$ and $0d_{5/2}$\norbitals for both systems is reduced by a factor of approximately 0.5 compared\nto the independent single-particle model, or about 0.6 when compared to the\nshell model. This finding strongly contrasts with results deduced from\nintermediate-energy knockout reactions between similar nuclei on targets of\n$^{9}$Be and $^{12}$C. The simultaneous technique used removes many systematic\nuncertainties.", + "category": "nucl-ex" + }, + { + "text": "Measurement of longitudinal flow de-correlations in Pb+Pb collisions at\n $\\sqrt{s_\\mathrm{NN}} = 2.76$ and 5.02 TeV with the ATLAS detector: Measurements of longitudinal flow decorrelations are presented for charged\nparticles in the pseudorapidity range $|\\eta|<2.4$ using 7 $\\mu$b$^{-1}$ and\n470 $\\mu$b$^{-1}$ of Pb+Pb collisions at $\\sqrt{s_{\\textrm{NN}}}=2.76$ and 5.02\nTeV, respectively, recorded by the ATLAS detector at the LHC. It is found that\nthe correlation between the harmonic flow coefficients $v_n$ measured in two\nseparated $\\eta$ intervals does not factorise into the product of\nsingle-particle coefficients, and this breaking of factorisation, or flow\ndecorrelation, increases linearly with the $\\eta$ separation between the\nintervals. The slopes for this flow decorrelation are found to be larger at\n2.76 TeV than 5.02 TeV. Higher-order moments of the correlations are also\nmeasured, and the corresponding linear coefficients for the\n$k^{\\textrm{th}}$-moment of the $v_n$ are found to be proportional to $k$ for\n$v_3$, but not for $v_2$. The decorrelation effect is separated into\ncontributions from the magnitude of $v_n$ and the event-plane orientation\nchanging with $\\eta$. These two contributions are found to be comparable. The\nlongitudinal flow correlations are also measured between $v_n$ of different\norder in $n$. The longitudinal fluctuations of $v_2$ and $v_3$ are found to be\nindependent of each other, while the longitudinal fluctuations of $v_4$ and\n$v_5$ are found to be driven by the nonlinear contribution from $v_2^2$ and\n$v_2v_3$, respectively.", + "category": "nucl-ex" + }, + { + "text": "Measurements of the nuclear modification factor and elliptic flow of\n leptons from heavy-flavour hadron decays in Pb--Pb collisions at\n $\\sqrt{s_{\\rm NN}}$ = 2.76 and 5.02 TeV with ALICE: We present the ALICE results on the nuclear modification factor and elliptic\nflow of electrons and muons from open heavy-flavour hadron decays at\nmid-rapidity and forward rapidity in Pb--Pb collisions at $\\sqrt{s_{\\rm NN}}$ =\n2.76 and 5.02 TeV for different centrality intervals. The results are compared\nto model calculations that include interactions of heavy quarks with the\nmedium.", + "category": "nucl-ex" + }, + { + "text": "Strong interaction studies with kaonic atoms: The strong interaction of antikaons (K-) with nucleons and nuclei in the low\nenergy regime represents an active research field connected intrinsically with\nfew-body physics. There are important open questions like the question of\nantikaon nuclear bound states - the prototype system being K-pp. A unique and\nrather direct experimental access to the antikaon-nucleon scattering lengths is\nprovided by precision X-ray spectroscopy of transitions in low-lying states of\nlight kaonic atoms like kaonic hydrogen isotopes. In the SIDDHARTA experiment\nat the electron-positron collider DA?NE of LNF-INFN we measured the most\nprecise values of the strong interaction observables, i.e. the strong\ninteraction on the 1s ground state of the electromagnetically bound K-p atom\nleading to a hadronic shift and a hadronic broadening of the 1s state. The\nSIDDHARTA result triggered new theoretical work which achieved major progress\nin the understanding of the low-energy strong interaction with strangeness.\nAntikaon-nucleon scattering lengths have been calculated constrained by the\nSIDDHARTA data on kaonic hydrogen. For the extraction of the isospin-dependent\nscattering lengths a measurement of the hadronic shift and width of kaonic\ndeuterium is necessary. Therefore, new X-ray studies with the focus on kaonic\ndeuterium are in preparation (SIDDHARTA2). Many improvements in the\nexperimental setup will allow to measure kaonic deuterium which is challenging\ndue to the anticipated low X-ray yield. Especially important are the data on\nthe X-ray yields of kaonic deuterium extracted from a exploratory experiment\nwithin SIDDHARTA.", + "category": "nucl-ex" + }, + { + "text": "Accessing the Sign and Magnitude of $\u0394$G via high $p_{T}$,\n $A_{LL}^{\u03c0^{\\pm}}$ in Polarized p+p Collisions at PHENIX: The double-helicity asymmetries ($A_{LL}$) of $\\pi^{+}$ and $\\pi^{-}$\nproduction in polarized proton proton collisions are specially interesting\nprobes of the gluon's polarization. Relative differences among $A_{LL}$ of\npositive, neutral, and negative pions at high transverse momentum are sensitive\nto the sign and of magnitude of $\\Delta$G. Quark-gluon (qg) scattering starts\nto dominate mid-rapidity pion production at RHIC at transverse momenta above\n5GeV/c. In this kinematic region the favored and unfavored fragmentation\nfunctions for each pion species are sensitive to both the gluon and the quark\ndistributions, with different flavors having different weights for each pion\nspecies. Charged pion asymmetry measurements will be an important component in\nfuture global analyses, aiming to determine the gluon polarization over a wide\nrange in x, the most recent results using polarized longitudinal data at\n$\\sqrt{s}=$200GeV, are presented.", + "category": "nucl-ex" + }, + { + "text": "High-Intensity and High-Brightness Source of Moderated Positrons Using a\n Brilliant gamma Beam: Presently large efforts are conducted towards the development of highly\nbrilliant gamma beams via Compton back scattering of photons from a\nhigh-brilliance electron beam, either on the basis of a normal-conducting\nelectron linac or a (superconducting) Energy Recovery Linac (ERL). Particularly\nERL's provide an extremely brilliant electron beam, thus enabling to generate\nhighest-quality gamma beams. A 2.5 MeV gamma beam with an envisaged intensity\nof 10^15 s^-1, as ultimately envisaged for an ERL-based gamma-beam facility,\nnarrow band width (10^-3), and extremely low emittance (10^-4 mm^2 mrad^2)\noffers the possibility to produce a high-intensity bright polarized positron\nbeam. Pair production in a face-on irradiated W converter foil (200 micron\nthick, 10 mm long) would lead to the emission of 2 x 10^13 (fast) positrons per\nsecond, which is four orders of magnitude higher compared to strong radioactive\n^22Na sources conventionally used in the laboratory.Using a stack of converter\nfoils and subsequent positron moderation, a high-intensity low-energy beam of\nmoderated positrons can be produced. Two different source setups are presented:\na high-brightness positron beam with a diameter as low as 0.2 mm, and a\nhigh-intensity beam of 3 x 10^11 moderated positrons per second. Hence,\nprofiting from an improved moderation efficiency, the envisaged positron\nintensity would exceed that of present high-intensity positron sources by a\nfactor of 100.", + "category": "nucl-ex" + }, + { + "text": "Neutron beta-decay, Standard Model and cosmology: The precise value of the neutron lifetime is of fundamental importance to\nparticle physics and cosmology. The neutron lifetime recently obtained, 878.5\n+/- 0.7stat +/- 0.3sys s, is the most accurate one to date. The new result for\nthe neutron lifetime differs from the world average value by 6.5 standard\ndeviations. The impact of the new result on testing of Standard Model and on\ndata analysis for the primordial nucleosynthesis model is scrutinized.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the $\u03b2^+$ and orbital electron-capture decay rates in\n fully-ionized, hydrogen-like, and helium-like $^{140}$Pr ions: We report on the first measurement of the $\\beta^+$- and orbital electron\ncapture decay rates of $^{140}$Pr nuclei with the most simple electron\nconfigurations: bare nuclei, hydrogen-like and helium-like ions. The measured\nelectron capture decay constant of hydrogen-like $^{140}$Pr$^{58+}$ ions is\nabout 50% larger than that of helium-like $^{140}$Pr$^{57+}$ ions. Moreover,\n$^{140}$Pr ions with one bound electron decay faster than neutral\n$^{140}$Pr$^{0+}$ atoms with 59 electrons. To explain this peculiar observation\none has to take into account the conservation of the total angular momentum,\nsince only particular spin orientations of the nucleus and of the captured\nelectron can contribute to the allowed decay.", + "category": "nucl-ex" + }, + { + "text": "Inclusive photon production at forward rapidities using PMD in p-Pb\n collisions at $\\sqrt{\\it{s}_{\\rm{NN}}} = 8.16$ TeV with ALICE: We report on the performance studies of two correction methods, namely the\nefficiency-purity method and the Bayesian unfolding method applied to the\npseudorapidity distribution of photons. The pseudorapidity distribution of\ninclusive photons at forward rapidities in the range \\mbox{\\small\n$(2.3<\\eta<3.9)$} in p\\textendash Pb collisions at $\\sqrt{\\it{s}_{\\rm{NN}}} =\n8.16$ TeV is obtained with the HIJING Monte Carlo event generator. The\nsimulated data samples were obtained from the Photon Multiplicity Detector\n(PMD) in ALICE.", + "category": "nucl-ex" + }, + { + "text": "Direct photons ~basis for characterizing heavy ion collisions~: After years of experimental and theoretical efforts, direct photons become a\nstrong and reliable tool to establish the basic characteristics of a hot and\ndense matter produced in heavy ion collisions. The recent direct photon\nmeasurements are reviewed and a future prospect is given.", + "category": "nucl-ex" + }, + { + "text": "New Narrow $N(1685)$ and $N(1726)$? Remarks on the Interpretation of the\n Neutron Anomaly as an Interference Phenomenon: Different interpretations of narrow structures at $W\\sim 1.68$ and $W\\sim\n1.72$ GeV observed in several reactions are discussed. It is questionable\nwhether interference phenomena could explain the whole complex of experimental\nfindings. More probable hypotheses would be the existence of one or two narrow\nresonances $N(1685)$ and $N(1726)$ and/or the sub-threshold virtual $K\\Sigma$\nand $\\omega p$ production (cusps).", + "category": "nucl-ex" + }, + { + "text": "Evolution of the $\u03b3$-ray strength function in neodymium isotopes: The experimental gamma-ray strength functions (gamma-SFs) of 142,144-151Nd\nhave been studied for gamma-ray energies up to the neutron separation energy.\nThe results represent a unique set of gamma-SFs for an isotopic chain with\nincreasing nuclear deformation. The data reveal how the low-energy enhancement,\nthe scissors mode and the pygmy dipole resonance evolve with nuclear\ndeformation and mass number. The data indicate that the mechanisms behind the\nlow-energy enhancement and the scissors mode are decoupled from each other.", + "category": "nucl-ex" + }, + { + "text": "A No-Go Theorem for Matter-Wave Interferometry with Application to the\n Neutron's Electric-Dipole Moment: A theorem that relies only on the unitary property of the Schroedinger\nequation and not upon any classical or semi-classical approximation negates\nsome, but not all, suggestions that have been made for measuring the neutron's\nelectric-dipole moment by interferometry.", + "category": "nucl-ex" + }, + { + "text": "The Majorana Demonstrator: A Search for Neutrinoless Double-beta Decay\n of 76Ge: Neutrinoless double-beta decay is a hypothesized process where in some\neven-even nuclei it might be possible for two neutrons to simultaneously decay\ninto two protons and two electrons without emitting neutrinos. This is possible\nonly if neutrinos are Majorana particles, i.e. fermions that are their own\nantiparticles. Neutrinos being Majorana particles would explicitly violate\nlepton number conservation, and might play a role in the matter-antimatter\nasymmetry in the universe. The observation of neutrinoless double-beta decay\nwould also provide complementary information related to neutrino masses. The\nMajorana Collaboration is constructing the Majorana Demonstrator, a 40-kg\nmodular germanium detector array, to search for the Neutrinoless double-beta\ndecay of 76Ge and to demonstrate a background rate at or below 3\ncounts/(ROI-t-y) in the 4 keV region of interest (ROI) around the 2039 keV\nQ-value for 76Ge Neutrinoless double-beta decay. In this paper, we discuss the\nphysics of neutrinoless double beta decay and then focus on the Majorana\nDemonstrator, including its design and approach to achieve ultra-low\nbackgrounds and the status of the experiment.", + "category": "nucl-ex" + }, + { + "text": "Half Life of the Doubly-magic r-Process Nucleus 78Ni: Nuclei with magic numbers serve as important benchmarks in nuclear theory. In\naddition, neutron-rich nuclei play an important role in the astrophysical rapid\nneutron-capture process (r-process). 78Ni is the only doubly-magic nucleus that\nis also an important waiting point in the r-process, and serves as a major\nbottleneck in the synthesis of heavier elements. The half-life of 78Ni has been\nexperimentally deduced for the first time at the Coupled Cyclotron Facility of\nthe National Superconducting Cyclotron Laboratory at Michigan State University,\nand was found to be 110 (+100 -60) ms. In the same experiment, a first\nhalf-life was deduced for 77Ni of 128 (+27 -33) ms, and more precise half-lives\nwere deduced for 75Ni and 76Ni of 344 (+20 -24) ms and 238 (+15 -18) ms\nrespectively.", + "category": "nucl-ex" + }, + { + "text": "Kaon pair production in proton-nucleus collisions at 2.83 GeV kinetic\n energy: The production of non-phi K+K- pairs by protons of 2.83 GeV kinetic energy on\nC, Cu, Ag, and Au targets has been investigated using the COSY-ANKE magnetic\nspectrometer. The K- momentum dependence of the differential cross section has\nbeen measured at small angles over the 0.2--0.9 GeV/c range. The comparison of\nthe data with detailed model calculations indicates an attractive K- -nucleus\npotential of about -60 MeV at normal nuclear matter density at a mean momentum\nof 0.5 GeV/c. However, this approach has difficulty in reproducing the\nsmallness of the observed cross sections at low K- momenta.", + "category": "nucl-ex" + }, + { + "text": "Broken axial symmetry as essential feature to predict radiative capture\n in heavy nuclei: Cross sections for neutron capture in the range of unresolved resonances are\npredicted for more than 140 spin-0 target nuclei with A > 50. Allowing the\nbreaking of spherical and axial symmetry in nearly all these nuclei a combined\nparameterization for both, level density and photon strength is obtained which\nemploys a surprisingly small number of parameters only. The strength functions\nused are based on a global fit to IVGDR shapes by the sum of three Lorentzians.\nThey are based on theoretical predictions for the A-dependence of pole energies\nand spreading widths and add up to the TRK sum rule. For the small spins\nreached by capture resonance spacings are well described by a level density\nparameter close to the nuclear matter value; a significant collective\nenhancement is apparent due to the deviation from axial symmetry. Reliable\npredictions for compound nuclear reactions also outside the valley of stability\n(as important for nuclear astrophysics and for the transmutation of nuclear\nwaste) are expected to result from the global parameterization presented.", + "category": "nucl-ex" + }, + { + "text": "Determination of shear forces inside the proton: We report on the first determination of the shear forces quarks inside the\nproton from experimental data on deeply virtual Compton scattering. The maximum\nshear force of approximately 40 MeV/fm occurs near 0.6 fm from the proton\ncenter, indicating where confinement forces may be strongest. On the\nmacroscopic scale of the earth surface, this force corresponds to the weight of\na mass of about 650 kg. The shear forces in the proton reverse direction at r =\n0.45 fm from the center.", + "category": "nucl-ex" + }, + { + "text": "Measurements of Ks, Lambda and Xi from Au+Au collisions at \\sqrt{s_NN} =\n 7.7, 11.5 and 39 GeV in STAR: We report on the measurements of Ks, Lambda and Xi spectra at mid-rapidity\n(|y|<0.5) in the most central (0-5%) Au+Au collisions at \\sqrt{s_NN} = 7.7,\n11.5 and 39 GeV from the STAR experiment. The extracted yields and the\ncorresponding data from Pb+Pb collisions measured by the NA49 and CERES\nexperiments at SPS are consistent. The Lambda, Anti-Lambda, Xi- and Xi+ to pion\nratios agree well with the predictions from a statistical hadronization model\nat all three energies.", + "category": "nucl-ex" + }, + { + "text": "Strong Interaction Physics at the Luminosity Frontier with 22 GeV\n Electrons at Jefferson Lab: This document presents the initial scientific case for upgrading the\nContinuous Electron Beam Accelerator Facility (CEBAF) at Jefferson Lab (JLab)\nto 22 GeV. It is the result of a community effort, incorporating insights from\na series of workshops conducted between March 2022 and April 2023. With a track\nrecord of over 25 years in delivering the world's most intense and precise\nmulti-GeV electron beams, CEBAF's potential for a higher energy upgrade\npresents a unique opportunity for an innovative nuclear physics program, which\nseamlessly integrates a rich historical background with a promising future. The\nproposed physics program encompass a diverse range of investigations centered\naround the nonperturbative dynamics inherent in hadron structure and the\nexploration of strongly interacting systems. It builds upon the exceptional\ncapabilities of CEBAF in high-luminosity operations, the availability of\nexisting or planned Hall equipment, and recent advancements in accelerator\ntechnology. The proposed program cover various scientific topics, including\nHadron Spectroscopy, Partonic Structure and Spin, Hadronization and Transverse\nMomentum, Spatial Structure, Mechanical Properties, Form Factors and Emergent\nHadron Mass, Hadron-Quark Transition, and Nuclear Dynamics at Extreme\nConditions, as well as QCD Confinement and Fundamental Symmetries. Each topic\nhighlights the key measurements achievable at a 22 GeV CEBAF accelerator.\nFurthermore, this document outlines the significant physics outcomes and unique\naspects of these programs that distinguish them from other existing or planned\nfacilities. In summary, this document provides an exciting rationale for the\nenergy upgrade of CEBAF to 22 GeV, outlining the transformative scientific\npotential that lies within reach, and the remarkable opportunities it offers\nfor advancing our understanding of hadron physics and related fundamental\nphenomena.", + "category": "nucl-ex" + }, + { + "text": "CNN-based event classification for alpha-decay events in nuclear\n emulsion: We developed an efficient classifier that sorts alpha-decay events from\nvarious vertex-like objects in nuclear emulsion using a convolutional neural\nnetwork (CNN). Alpha-decay events in the emulsion are standard calibration\nsources for the relation between the track length and kinetic energy in each\nemulsion sheet. We trained the CNN using 15,885 images of vertex-like objects\nincluding 906 alpha-decay events and tested it using a dataset of 46,948 images\nincluding 255 alpha-decay events. By tuning the hyperparameters of the CNN, the\ntrained models achieved an Average Precision Score of 0.740 +/- 0.009 for the\ntest dataset. For the model obtained, a discrimination threshold of the\nclassification can be arbitrarily adjusted according to the balance between the\nprecision and recall. The precision and recall of the classification using\nprevious method without a CNN were 0.081 +/- 0.006 and 0.788 +/- 0.056,\nrespectively, for the same dataset. By contrast, the developed classifier\nobtained a precision of 0.547 +/- 0.025 when a similar recall value of 0.788\nwas set. The developed CNN method reduced the human load for further visual\ninspection after the classification by approximately 1/7 compared to the\nestimated load of the former method without a CNN.", + "category": "nucl-ex" + }, + { + "text": "First observation of excited states in 173Hg: The neutron-deficient nucleus 173Hg has been studied following\nfusion-evaporation reactions. The observation of gamma rays decaying from\nexcited states are reported for the first time and a tentative level scheme is\nproposed. The proposed level scheme is discussed within the context of the\nsystematics of neighbouring neutron-deficient Hg nuclei. In addition to the\ngamma-ray spectroscopy, the alpha decay of this nucleus has been measured\nyielding superior precision to earlier measurements.", + "category": "nucl-ex" + }, + { + "text": "Structure of 23Al from one-proton breakup reaction and astrophysical\n implications: The ground state of the proton-rich nucleus 23Al has been studied by\none-proton removal on a carbon target at about 50 MeV/nucleon using the EXOGAM\n+ SPEG experimental setup at GANIL. Longitudinal momentum distributions of the\n22Mg breakup fragments, inclusive and in coincidence with gamma rays\nde-exciting the residues, were measured. The ground-state structure of 23Al is\nfound to be a configuration mixing of a d-orbital valence proton coupled to\nfour core states - 0$^{+}_{gs}$, 2$^{+}_{1}$, 4$^{+}_{1}$, 4$^{+}_{2}$. We\nconfirm the ground state spin and parity of 23Al as $J^{\\pi} = 5/2^{+}$. The\nmeasured exclusive momentum distributions are compared with extended Glauber\nmodel calculations to extract spectroscopic factors and asymptotic\nnormalization coefficients (ANCs). The spectroscopic factors are presented in\ncomparison with those obtained from large-scale shell model calculations. We\ndetermined the asymptotic normalization coefficient of the nuclear system\n$^{23}$Al$_{gs}$ $\\rightarrow$ $^{22}$Mg(0$^{+}$) + p to be\n$C^{2}_{d_{5/2}}$($^{23}Al_{gs}$) = (3.90 $\\pm$ 0.44) $\\times$ 10$^{3}$\nfm$^{-1}$, and used it to infer the stellar reaction rate of the direct\nradiative proton capture $^{22}$Mg(p,$\\gamma$)$^{23}$Al. Astrophysical\nimplications related to $^{22}$Na nucleosynthesis in ONe novae and the use of\none-nucleon breakup at intermediate energies as an indirect method in nuclear\nastrophysics are discussed.", + "category": "nucl-ex" + }, + { + "text": "Quadrupole Moments of Collective Structures up to Spin $\\sim$ $65\\hbar$\n in $^{157}$Er and $^{158}$Er: A Challenge for Understanding Triaxiality in\n Nuclei: The transition quadrupole moments, $Q_{\\rm t}$, of four weakly populated\ncollective bands up to spin $\\sim$ $65\\hbar$ in $^{157,158}$Er have been\nmeasured to be ${\\sim}11 {\\rm eb}$ demonstrating that these sequences are\nassociated with large deformations. However, the data are inconsistent with\ncalculated values from cranked Nilsson-Strutinsky calculations that predict the\nlowest energy triaxial shape to be associated with rotation about the short\nprincipal axis. The data appear to favor either a stable triaxial shape\nrotating about the intermediate axis or, alternatively, a triaxial shape with\nlarger deformation rotating about the short axis. These new results challenge\nthe present understanding of triaxiality in nuclei.", + "category": "nucl-ex" + }, + { + "text": "Measurement of single electrons and implications for charm production in\n Au+Au collisions at sqrt(s_NN)= 130 GeV: Transverse momentum spectra of electrons from Au+Au collisions at sqrt(s_NN)\n= 130 GeV have been measured by the PHENIX experiment at RHIC. The spectra show\nan excess above the background from photon conversions and light hadron decays.\nThe electron signal is consistent with that expected from semi-leptonic decays\nof charm. The yield of the electron signal dN_e/dy for p_T > 0.8 GeV/c is 0.025\n+/- 0.004 (stat.) +/- 0.010 (sys.) in central collisions, and the corresponding\ncharm cross section is 380 +/- 60 (stat.) +/- 200 (sys.) micro barns per binary\nnucleon-nucleon collision.", + "category": "nucl-ex" + }, + { + "text": "First measurements of the ^16O(e,e'pn)^14N reaction: This paper reports on the first measurement of the ^16O(e,e'pn)^14N reaction.\nData were measured in kinematics centred on a super-parallel geometry at energy\nand momentum transfers of 215 MeV and 316 MeV/c. The experimental resolution\nwas sufficient to distinguish groups of states in the residual nucleus but not\ngood enough to separate individual states. The data show a strong dependence on\nmissing momentum and this dependence appears to be different for two groups of\nstates in the residual nucleus. Theoretical calculations of the reaction using\nthe Pavia code do not reproduce the shape or the magnitude of the data.", + "category": "nucl-ex" + }, + { + "text": "Spectroscopy of $^{26}$F: The structure of the weakly-bound $^{26}_{\\;\\;9}$F$_{17}$ odd-odd nucleus,\nproduced from $^{27,28}$Na nuclei, has been investigated at GANIL by means of\nthe in-beam $\\gamma$-ray spectroscopy technique. A single $\\gamma$-line is\nobserved at 657(7) keV in $^{26}_{9}$F which has been ascribed to the decay of\nthe excited J=$2^+$ state to the J=1$^+$ ground state. The possible presence of\nintruder negative parity states in $^{26}$F is also discussed.", + "category": "nucl-ex" + }, + { + "text": "Probing dense and hot matter with low-mass dileptons and photons: Results on low-mass dileptons, covering the very broad energy range from the\nBEVALAC up to SPS are reviewed. The emphasis is on the open questions raised by\nthe intriguing results obtained so far and the prospects for addressing them in\nthe near future with the second generation of experiments, in particular HADES,\nNA60 and PHENIX.", + "category": "nucl-ex" + }, + { + "text": "New neutron-deficient isotopes from $^{78}$Kr fragmentation: In an experiment with the BigRIPS separator at the RIKEN Nishina Center, the\nfragmentation of a $^{78}$Kr beam allowed the observation of new\nneutron-deficient isotopes at the proton drip-line. Clean identification\nspectra could be produced and $^{63}$Se, $^{67}$Kr, and $^{68}$Kr were\nidentified for the first time. In addition, $^{59}$Ge was also observed. Three\nof these isotopes, $^{59}$Ge, $^{63}$Se, and $^{67}$Kr, are potential\ncandidates for ground-state two-proton radioactivity. In addition, the isotopes\n$^{58}$Ge, $^{62}$Se, and $^{66}$Kr were also sought but without success. The\npresent experiment also allowed the determination of production cross sections\nfor some of the most exotic isotopes. These measurements confirm the trend\nalready observed that the empirical parameterization of fragmentation cross\nsections, EPAX, significantly overestimates experimental cross sections in this\nmass region.", + "category": "nucl-ex" + }, + { + "text": "Identical pion intensity interferometry in central Au+Au collisions at\n 1.23A GeV: We investigate identical pion HBT intensity interferometry for central Au+Au\ncollisions at 1.23A GeV. High-statistics $\\pi^-\\pi^-$ and $\\pi^+\\pi^+$ data are\nmeasured with HADES at SIS18/GSI. The radius parameters, derived from the\ncorrelation function depending on relative momenta in the longitudinal-comoving\nsystem and parametrized as three-dimensional Gaussian distribution, are studied\nas function of transverse momentum. A substantial charge-sign difference of the\nsource radii is found, particularly pronounced at low transverse momentum. The\nextracted Coulomb-corrected source parameters agree well with a smooth\nextrapolation of the center-of-mass energy dependence established at higher\nenergies, extending the corresponding excitation functions down towards a very\nlow energy. Our data would thus rather disfavour any strong energy dependence\nof the radius parameters in the low energy region.", + "category": "nucl-ex" + }, + { + "text": "Hadronization and chirality in strongly interacting partonic matter -\n the future of the RHIC program: New physics and detector concepts for a future pp and heavy ion program at\nthe RHIC-II accelerator facility will be discussed. I will focus on hadronic\nobservables which enable us to gain a better understanding on the hadronization\nfrom a sQGP and the chiral symmetry restoration in a sQGP. The ultimate\nquestion of how matter acquires mass can be addressed by this program in a\ncomplementary way to the Higgs search in high energy physics. The contributions\nof the RHIC program to the study of QCD will be discussed in detail.", + "category": "nucl-ex" + }, + { + "text": "Neutron inelastic scattering in natural Cu as a background in\n neutrinoless double-beta decay experiments: Experiments designed to study rare processes, such as neutrinoless double\nbeta decay ($0\\nu\\beta\\beta$), are crucial tests for physics beyond the\nstandard model. These experiments rely on reducing the intrinsic radioactive\nbackground to unprecedented levels, while adequately shielding the detectors\nfrom external sources of radioactivity. An understanding of the potential for\nneutron excitation of the shielding and detector materials is important for\nobtaining this level of sensitivity. Using the broad-spectrum neutron beam at\nLANSCE, we have measured inelastic neutron scattering on $^{nat}$Cu. The goal\nof this work is focused on understanding the background rates from neutrons\ninteracting in these materials in regions around the Q-values of many candidate\n$0\\nu\\beta\\beta$ decay isotopes, as well as providing data for benchmarking\nMonte Carlo simulations of background events. Results: We extracted the level\ncross sections from the $\\gamma$ production cross section for 46 energy levels\nin $^{nat}$Cu . These level cross sections were compared with the available\nexperimental data, as well as the ENDF/B-VII evaluation for discrete levels. We\nalso examined the potential implications of our measurements on\n$0\\nu\\beta\\beta$ measurements and found that many of the commonly studied\n$0\\nu\\beta\\beta$ isotopes had Q-values below the cutoff for ENDF/B-VII\nevaluated discrete levels in either Cu nucleus.", + "category": "nucl-ex" + }, + { + "text": "Single-particle isomeric states in 121Pd and 117Ru: Neutron-rich nuclei were populated in a relativistic fission of 238U.\nGamma-rays with energies of 135 keV and 184 keV were associated with two\nisomeric states in 121Pd and 117Ru. Half-lives of 0.63(5) microseconds and\n2.0(3) micrisecondss were deduced and the isomeric states were interpreted in\nterms of deformed single-particle states.", + "category": "nucl-ex" + }, + { + "text": "Hot and Cold QCD White Paper from ALICE-USA: Input for 2023 U.S. Long\n Range Plan for Nuclear Science: The ALICE-USA collaboration presents its plans for the 2023 U.S. Long Range\nPlan for Nuclear Science.", + "category": "nucl-ex" + }, + { + "text": "Ultra-peripheral Au+Au collisions at PHENIX: Ultra-peripheral collisions (UPC) of heavy-ions involve long range\nelectromagnetic interactions at impact parameters twice larger than the nuclear\nradius, where no nucleon-nucleon collisions occur. The first measurement of\nphotoproduction of $J/\\psi$ and of two-photon production of high-mass $e^+ e^-$\npairs in ultra-peripheral nucleus-nucleus interactions will be presented, using\nAu+Au data at $\\sqrt{s_{_{NN}}}$ = 200 GeV. The measured cross sections at\nmidrapidity are consistent with various theoretical predictions.", + "category": "nucl-ex" + }, + { + "text": "Proton-proton correlations observed in two-proton decay of $^{19}$Mg and\n $^{16}$Ne: Proton-proton correlations were observed for the two-proton decays of the\nground states of $^{19}$Mg and $^{16}$Ne. The trajectories of the respective\ndecay products, $^{17}$Ne+p+p and $^{14}$O+p+p, were measured by using a\ntracking technique with microstrip detectors. These data were used to\nreconstruct the angular correlations of fragments projected on planes\ntransverse to the precursor momenta. The measured three-particle correlations\nreflect a genuine three-body decay mechanism and allowed us to obtain\nspectroscopic information on the precursors with valence protons in the $sd$\nshell.", + "category": "nucl-ex" + }, + { + "text": "Deuteron frozen spin polarized target for nd experiements at the VdG\n accelerator of Charles University: A frozen spin polarized deuteron target cooled by the 3He/4He dilution\nrefrigerator is described. Fully deuterated 1,2-propanediol was used as a\ntarget material. Deuteron vector polarization about 40% was obtained for the\ntarget in the shape of a cylinder of 2 cm diameter and 6 cm length. The target\nis intended for a study of 3N interactions at the polarized neutron beam\ngenerated by the Van de Graaff accelerator at the Charles University in Prague.", + "category": "nucl-ex" + }, + { + "text": "Multifragmentation and the Phase Transition: A Systematic Study of the\n MF of 1A GeV Au, La, and Kr: A systematic analysis of the multifragmentation (MF) in fully reconstructed\nevents from 1A GeV Au, La and Kr collisions with C has been performed. This\ndata is used to provide a definitive test of the variable volume version of the\nstatistical multifragmentation model (SMM). A single set of SMM parameters\ndirectly determined by the data and the semi-empiricalmass formula are used\nafter the adjustable inverse level density parameter, $\\epsilon_{o}$ is\ndetermined by the fragment distributions. The results from SMM for second stage\nmultiplicity, size of the biggest fragment and the intermediate mass fragments\nare in excellent agreement with the data. Multifragmentation thresholds have\nbeen obtained for all three systems using SMM prior to secondary decay. The\ndata indicate that both thermal excitation energy $E_{th}^{*}$ and the isotope\nratio temperature $T_{He-DT}$ decrease with increase in system size at the\ncritical point. The breakup temperature obtained from SMM also shows the same\ntrend as seen in the data. The SMM model is used to study the nature of the MF\nphase transition. The caloric curve for Kr exhibits back-bending (finite latent\nheat) while the caloric curves for Au and La are consistent with a continuous\nphase transition (nearly zero latent heat) and the values of the critical\nexponents $\\tau$, $\\beta$ and $\\gamma$, both from data and SMM, are close to\nthose for a 'liquid-gas' system for Au and La. We conclude that the larger\nCoulomb expansion energy in Au and La reduces the latent heat required for MF\nand changes the nature of the phase transition. Thus the Coulomb energy plays a\nmajor role in nuclear MF.", + "category": "nucl-ex" + }, + { + "text": "Discovery of Isotopes of Elements with Z $\\ge$ 100: Currently, 163 isotopes of elements with Z $\\ge$ 100 have been observed and\nthe discovery of these isotopes is discussed here. For each isotope a brief\nsynopsis of the first refereed publication, including the production and\nidentification method, is presented.", + "category": "nucl-ex" + }, + { + "text": "Flow Phenomena at AGS Energies: In this talk some of the latest data on directed sideward, elliptic, radial,\nand longitudinal flow at AGS energies will be reviewed. A method to identify\nthe reaction plane event by event and the measurement of its resolution will be\ndiscussed. The distributions of global observables (transverse energy E_T and\ncharged particle multiplicity N_c), as well as those of identified particles\nwill be shown. Finally, the data will be put in context with measurements at\nother beam energies. These systematics will then be discussed in terms of\npossible signatures of the QCD phase transition.", + "category": "nucl-ex" + }, + { + "text": "Analysis of a Cyclotron Based 400 MeV/u Driver System for a Radioactive\n Beam Facility: The creation of intense radioactive beams requires intense and energetic\nprimary beams. A task force analysis of this subject recommended an\nacceleration system capable of 400 MeV/u uranium at 1 particle uA as an\nappropriate driver for such a facility. The driver system should be capable of\naccelerating lighter ions at higher intensity such that a constant final beam\npower (~100kW) is maintained. This document is a more detailed follow on to the\nprevious analysis of such a system incorporating a cyclotron. The proposed\ndriver pre-acceleration system consists of an ion source, radio frequency\nquadrupole, and linac chain capable of producing a final energy of 30 MeV/u and\na charge (Q) to mass (A) of Q/A ~1/3. This acceleration system would be\nfollowed by a Separated Sector Cyclotron with a final output energy of 400\nMeV/u. This system provides a more cost-effective solution in terms of initial\ncapital investment as well as of operation compared to a fully linac system\nwith the same primary beam output parameters.", + "category": "nucl-ex" + }, + { + "text": "A Honeycomb Proportional Counter for Photon Multiplicity Measurement in\n the ALICE Experiment: A honeycomb detector consisting of a matrix of 96 closely packed hexagonal\ncells, each working as a proportional counter with a wire readout, was\nfabricated and tested at the CERN PS. The cell depth and the radial dimensions\nof the cell were small, in the range of 5-10 mm. The appropriate cell design\nwas arrived at using GARFIELD simulations. Two geometries are described\nillustrating the effect of field shaping. The charged particle detection\nefficiency and the preshower characteristics have been studied using pion and\nelectron beams. Average charged particle detection efficiency was found to be\n98%, which is almost uniform within the cell volume and also within the array.\nThe preshower data show that the transverse size of the shower is in close\nagreement with the results of simulations for a range of energies and converter\nthicknesses.", + "category": "nucl-ex" + }, + { + "text": "$\u03a9^-$ and $\\bar\u03a9^+$ production in Au+Au collisions at\n $\\sqrt{s_{NN}}$ = 130 and 200 GeV: Mid-rapidity Omega and anti-Omega production in Au+Au collisions at RHIC is\nstudied with the STAR experiment. We report preliminary results on yields and\nspectra at $\\sqrt{s_{NN}}$ = 130 and 200 GeV. Production relative to negatively\ncharged hadrons (h-) as well as thermal freeze-out and collective expansion are\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Multiplicity dependence of two-particle azimuthal correlations in pp\n collisions at the LHC: We present the measurements of particle pair yields per trigger particle\nobtained from di-hadron azimuthal correlations in pp collisions at $\\sqrt{s} =\n0.9$, $2.76$, and $7$ TeV recorded with the ALICE detector. The yields are\nstudied as a function of the charged particle multiplicity. Taken together with\nthe single particle yields the pair yields provide information about parton\nfragmentation at low transverse momenta, as well as on the contribution of\nmultiple parton interactions to particle production. Data are compared to\ncalculations using the PYTHIA6, PYTHIA8, and PHOJET event generators.", + "category": "nucl-ex" + }, + { + "text": "High precision determination of the $Q^2$-evolution of the Bjorken Sum: We present a significantly improved determination of the Bjorken Sum for\n0.6$\\leq Q^{2}\\leq$4.8 GeV$^{2}$ using precise new $g_{1}^{p}$ and $g_{1}^{d}$\ndata taken with the CLAS detector at Jefferson Lab. A higher-twist analysis of\nthe $Q^{2}$-dependence of the Bjorken Sum yields the twist-4 coefficient\n$f_{2}^{p-n}=-0.064 \\pm0.009\\pm_{0.036}^{0.032}$. This leads to the color\npolarizabilities $\\chi_{E}^{p-n}=-0.032\\pm0.024$ and\n$\\chi_{B}^{p-n}=0.032\\pm0.013$. The strong force coupling is determined to be\n$\\alpha_{s}^{\\overline{\\mbox{ MS}}}(M_{Z}^{2})=0.1124\\pm0.0061$, which has an\nuncertainty a factor of 1.5 smaller than earlier estimates using polarized DIS\ndata. This improvement makes the comparison between $\\alpha_{s}$ extracted from\npolarized DIS and other techniques a valuable test of QCD.", + "category": "nucl-ex" + }, + { + "text": "Low-Energy $\u039b-\\p$ Scattering Parameters from the $pp \\to\n pK^+\u039b$ Reaction: Constraints on the spin-averaged $\\Lambda p$ scattering length and effective\nrange have been obtained from measurements of the $pp\\to pK^+\\Lambda$ reaction\nclose to the production threshold by comparing model phase-space Dalitz plot\noccupations with experimental ones. The data fix well the position of the\nvirtual bound state in the $\\Lambda p$ system. Combining this with information\nfrom elastic $\\Lambda p$ scattering measurements at slightly higher energies,\ntogether with the fact that the hyperdeuteron is not bound, leads to a new\ndetermination of the low energy $\\Lambda p$ scattering parameters.", + "category": "nucl-ex" + }, + { + "text": "Early dissipation and viscosity: We consider dissipative phenomena due to the relaxation of an initial\nanisotropic local pressure in the fireball created in relativistic heavy-ion\ncollisions, both for the Bjorken boost-invariant case and for the azimuthally\nsymmetric radial expansion with boost-invariance. The resulting increase of the\nentropy can be counterbalanced by a suitable retuning of the initial\ntemperature. An increase of the transverse collective flow is observed. The\ninfluence of the shear viscosity on the longitudinal expansion is also studied.\nViscosity reduces the cooling rate from the longitudinal work and counteracts\nthe pressure gradients that accelerate the longitudinal flow.", + "category": "nucl-ex" + }, + { + "text": "9Li and 8He decays in GEANT4: The decays of cosmogenic nuclei such as $^9$Li and $^8$He represent one of\nthe largest irreducible backgrounds for reactor antineutrino experiments. The\ncorrect treatment of such decays are of fundamental importance in the study of\ncosmogenic backgrounds and in their rejection, hence the full chain of\nintermediate excited states must be accounted for. Currently the treatment in\nGEANT4 of the modelling of de-excitation of $^9$Be and $^8$Li, which are the\ndaughter nuclei of $^9$Li and $^8$He respectively, is not correct. $^9$Be\nexcited states should break into a neutron and two $\\alpha$'s, and $^8$Li\nexcited states should emit a neutron and possibly an $\\alpha$ and a triton\ndepending on the decay chain, whereas in GEANT4 they both reach the ground\nstate by emitting a gamma. Based on the available nuclear measurements we\nincluded the correct treatment of $^9$Li and $^8$He decays in GEANT4 and\ncompared the obtained results with the spectra published by the Double Chooz\ncollaboration finding an excellent agreement.", + "category": "nucl-ex" + }, + { + "text": "Study of the long-lived excited state in the neutron deficient nuclides\n $^{195,197,199}$Po by precision mass measurement: Direct mass measurements of the low-spin $3/2^{(-)}$ and high-spin\n$13/2^{(+)}$ states in the neutron-deficient isotopes $^{195}$Po, $^{197}$Po,\nand high-spin $13/2^{(+)}$ state in $^{199}$Po were performed with the\nPenning-trap mass spectrometer ISOLTRAP at ISOLDE-CERN. These measurements\nallow the determination of the excitation energy of the isomeric state arising\nfrom the $\\nu$i$_{13/2}$ orbital in $^{195,197}$Po. Additionally, the\nexcitation energy of isomeric states of lead, radon, and radium isotopes in\nthis region were obtained from $\\alpha$-decay chains. The new excitation\nenergies complete the knowledge of the energy systematics in the region and\nconfirm for the first time that the $13/2^{(+)}$ states remain isomeric,\nindependent of the number of valence neutrons.", + "category": "nucl-ex" + }, + { + "text": "Nuclear physics for geo-neutrino studies: Geo-neutrino studies are based on theoretical estimates of geo-neutrino\nspectra. We propose a method for a direct measurement of the energy\ndistribution of antineutrinos from decays of long-lived radioactive isotopes.\nWe present preliminary results for the geo-neutrinos from Bi-214 decay, a\nprocess which accounts for about one half of the total geo-neutrino signal. The\nfeeding probability of the lowest state of Bi-214 - the most important for\ngeo-neutrino signal - is found to be p_0 = 0.177 \\pm 0.004 (stat)\n^{+0.003}_{-0.001} (sys), under the hypothesis of Universal Neutrino Spectrum\nShape (UNSS). This value is consistent with the (indirect) estimate of the\nTable of Isotopes (ToI). We show that achievable larger statistics and\nreduction of systematics should allow to test possible distortions of the\nneutrino spectrum from that predicted using the UNSS hypothesis. Implications\non the geo-neutrino signal are discussed.", + "category": "nucl-ex" + }, + { + "text": "Ultrarelativistic heavy ion collisions: the first billion seconds: I first review the early history of the ultrarelativistic heavy ion program,\nstarting with the 1974 Bear Mountain Workshop, and the 1983 Aurora meeting of\nthe U.S. Nuclear Science Committee, just one billion seconds ago, which laid\nout the initial science goals of an ultrarelativistic collider. The primary\ngoal, to discover the properties of nuclear matter at the highest energy\ndensities, included finding new states of matter -- the quark-gluon plasma\nprimarily -- and to use collisions to open a new window on related problems of\nmatter in cosmology, neutron stars, supernovae, and elsewhere. To bring out how\nthe study of heavy ions and hot, dense matter in QCD has been fulfilling these\ngoals. I concentrate on a few topics, the phase diagram of matter in QCD, and\nconnections of heavy ion physics to cold atoms, cosmology, and neutron stars.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the invariant mass distributions for the pp -> ppeta'\n reaction at excess energy of Q = 16.4 MeV: The proton-proton and proton-eta' invariant mass distributions have been\ndetermined for the pp -> ppeta' reaction at an excess energy of Q = 16.4 MeV.\nThe measurement was carried out using the COSY-11 detector setup and the proton\nbeam of the cooler synchrotron COSY. The shapes of the determined invariant\nmass distributions are similar to those of the pp -> ppeta reaction and reveal\nan enhancement for large relative proton-proton momenta. This result, together\nwith the fact that the proton-eta interaction is much stronger that the\nproton-eta' interaction, excludes the hypothesis that the observed enhancement\nis caused by the interaction between the proton and the meson.", + "category": "nucl-ex" + }, + { + "text": "Participant and spectator scaling of spectator fragments in Au+Au and\n Cu+Cu collisions at sqrt(sNN) = 19.6 and 22.4 GeV: Spectator fragments resulting from relativistic heavy ion collisions,\nconsisting of single protons and neutrons along with groups of stable nuclear\nfragments up to Nitrogen (Z=7), are measured in PHOBOS. These fragments are\nobserved in Au+Au (sqrt(sNN)=19.6 GeV) and Cu+Cu (22.4 GeV) collisions at high\npseudorapidity ($\\eta$). The dominant multiply-charged fragment is the tightly\nbound Helium ($\\alpha$), with Lithium, Beryllium, and Boron all clearly seen as\na function of collision centrality and pseudorapidity. We observe that in Cu+Cu\ncollisions, it becomes much more favorable for the $\\alpha$ fragments to be\nreleased than Lithium. The yields of fragments approximately scale with the\nnumber of spectator nucleons, independent of the colliding ion. The shapes of\nthe pseudorapidity distributions of fragments indicate that the average\ndeflection of the fragments away from the beam direction increases for more\ncentral collisions. A detailed comparison of the shapes for $\\alpha$ and\nLithium fragments indicates that the centrality dependence of the deflections\nfavors a scaling with the number of participants in the collision.", + "category": "nucl-ex" + }, + { + "text": "Direct photon production at low transverse momentum in proton-proton\n collisions at $\\sqrt{s}$ = 2.76 and 8 TeV: Measurements of inclusive and direct photon production at mid-rapidity in pp\ncollisions at $\\sqrt{s}=2.76$ and 8 TeV are presented by the ALICE experiment\nat the LHC. The results are reported in transverse momentum ranges of\n$0.47$\nGeV/$c$ is at least one $\\sigma$ above unity and consistent with expectations\nfrom next-to-leading order pQCD calculations.", + "category": "nucl-ex" + }, + { + "text": "Electromagnetic transition from the 4$^+$ to 2$^+$ resonance in $^8$Be\n measured via the radiative capture in $^4$He+$^4$He: An earlier measurement on the 4$^+$ to 2$^+$ radiative transition in $^8$Be\nprovided the first electromagnetic signature of its dumbbell-like shape.\nHowever, the large uncertainty in the measured cross section does not allow a\nstringent test of nuclear structure models. The present paper reports a more\nelaborate and precise measurement for this transition, via the radiative\ncapture in the $^4$He+$^4$He reaction, improving the accuracy by about a factor\nof three. The {\\it ab initio} calculations of the radiative transition strength\nwith improved three-nucleon forces are also presented. The experimental results\nare compared with the predictions of the alpha cluster model and {\\it ab\ninitio} calculations.", + "category": "nucl-ex" + }, + { + "text": "A novel approach for extracting model-independent nuclear level\n densities far from stability: The level density of quantum states in statistical mesoscopic systems is a\ncritical input for various fields of physics, including nuclear physics,\nnuclear astrophysics, atomic physics and their applications. In atomic nuclei,\nthe level density is a fundamental measure of their complex structure at\nrelatively high energies. Here we present the first model-independent\nmeasurement of the absolute partial nuclear level density for a short-lived\nunstable nucleus. For this purpose, we introduce the ``Shape method'' to\nextract the shape of the $\\gamma$-ray strength function. Combining the Shape\nmethod with the existing $\\beta$-Oslo technique allows the extraction of the\nnuclear level density without the need for theoretical input. We benchmark the\nShape method using results for the stable $^{76}$Ge nucleus, finding an\nexcellent agreement to previous experimental results. We apply the Shape method\nto new experimental data on the short-lived $^{88}$Kr nucleus. Our method opens\nthe door for measurements of the nuclear level density and $\\gamma$-ray\nstrength function far away from stability, a pivotal input required to\nunderstand the role of exotic nuclei in forming the cosmos.", + "category": "nucl-ex" + }, + { + "text": "Results on hyperon production from the NA57 experiment: Recent results on hyperon production in Pb--Pb collisions from the NA57\nexperiment are reported. Strangeness enhancement and the transverse mass\nspectra properties at 158 GeV per nucleon are described.", + "category": "nucl-ex" + }, + { + "text": "Spectroscopic studies of Dy-168,170 using CLARA and PRISMA: Preliminary results from an experiment aiming at Dy-170. Submitted to the LNL\nAnnual Report 2008.", + "category": "nucl-ex" + }, + { + "text": "First-order event plane correlated directed and triangular flow from\n fixed-target energies at RHIC-STAR: We report the measurement of first-order event plane correlated directed flow\n$(v_1)$ and triangular flow $v_3$ for identified hadrons ($\\pi^{\\pm}$,\n$K^{\\pm}$, and $p$), net-particle (net-K, net-p), and light nuclei ($d$ and\n$t$) in Au+Au collisions at $\\sqrt{s_{\\text{NN}}}$ = 3.2, 3.5, and 3.9 GeV in\nfixed-target mode from the second phase of beam energy scan (BES-II) program at\nRHIC-STAR. The $v_1$ slopes at mid-rapidity for identified hadrons and\nnet-particles except $\\pi^{+}$ are found to be positive, implying the effect of\ndominant repulsive baryonic interactions. The slope of $v_1$ for net-kaon\nundergoes a sign change from negative to positive at a lower collision energy\ncompared to net-proton. An approximate atomic mass number scaling is observed\nin the measured $v_1$ slopes of light nuclei at mid-rapidity, which favours the\nnucleon coalescence mechanism for the production of light nuclei. The $v_3$\nslope for all particles decreases in magnitude with increasing collision\nenergy, suggesting a notable integrated impact of the mean-field, baryon\nstopping, and collision geometry at lower collision energies.", + "category": "nucl-ex" + }, + { + "text": "Direct observation of the decay of first excited Hoyle state in $^{12}$C: An excited state of $^{12}$C having excitation energy E$_x \\sim$ 9.65 $\\pm$\n0.02 MeV and width (FWHM) $\\sim607\\pm$ 55 keV, which decays to three $ \\alpha\n$-particles via Hoyle state ($E_x \\sim$ 7.65 MeV), has been directly identified\nfor the first time in the exclusive inelastic scattering of 60 MeV $^{4}$He on\n$^{12}$C, measured in coincidence with the recoiling $^{12}$C$ ^* $ Hoyle state\n(decaying mostly as $^{12}$C$ ^* $ $\\rightarrow \\ ^{8} $Be + $ \\alpha $\n$\\rightarrow \\ \\alpha + \\alpha + \\alpha$) by event-by-event kinematic\nreconstruction of the completely detected (4$ \\alpha $) events. This state is\nlikely to be a candidate for 2$_2^+$ first excited Hoyle state, the existence\nof which has recently been indirectly evidenced from the recent inclusive\ninelastic scattering studies.", + "category": "nucl-ex" + }, + { + "text": "Fission Parameters Measurements for Np, Pu, Am, and Cm Isotopes Inside a\n Salt Blanket Micromodel: The MAKET zero-power heavy water reactor has been used at ITEP to measure the\nfission characteristics of the Np, Pu, Am, and Cm isotopes in the\n0.52NaF+0.48ZrF_4 melt-filled salt blanket micromodel. The 237Np(n,f),\n238Pu(n,f), 239Pu(n,f), 240Pu(n,f), 241Pu(n,f), 242m^Am(n,f), 243Cm(n,f),\n245Cm(n,f), 247Cm(n,f), 238U(n,f), 238U(n,g), 235U(n,f) fission reaction rates\nhave been measured. The neutron spectrum in the isotope irradiation locations\nwas monitored by measuring the rates of the (235U(n,f), 238U(n,g), 55Mn(n,g),\n63Cu(n,g), 176Lu(n,g), 197Au(n,g), 115In(n,n'), 27Al(n,4He), and 64Zn(n,p))\nreactions whose cross sections have been commonly accepted. The measured\nfunctionals are compared with the respective results of MCNP code simulation\nobtained using the ENDF/B6 and JENDL3.2 neutron databases.", + "category": "nucl-ex" + }, + { + "text": "Possibilities of future double beta decay experiments to investigate\n inverted and normal ordering region of neutrino mass: An overview of modern experiments on the search for neutrinoless double decay\nis presented. The obtained limits on the effective mass of the Majorana\nneutrino $\\langle m_{\\nu} \\rangle$ are discussed taking into account the\nuncertainties in the value of the nuclear matrix elements (NMEs) and the value\nof the axial-vector constant $g_A$. Predictions for the values of $\\langle\nm_{\\nu} \\rangle$ from the results of oscillation experiments and modern\ncosmological data are presented. The possibilities of the next generation\nexperiments with sensitivity to $\\langle m_{\\nu} \\rangle$ at the level of\n$\\sim$ 10-50 meV (studying mainly the inverted ordering (IO) region) are\ndiscussed. %Description of the most developed and promising projects is\npresented. The prospects for studying the normal ordering (NO) region are\ndiscussed too. It is shown that the possibilities of studying the NO depend on\nthe mass of the lightest neutrino m$_0$. In the limiting case of small mass\n(m$_0$ $\\le$ 0.1 meV), the values of $\\langle m_{\\nu} \\rangle$ $\\approx$ 1-4\nmeV are predicted, which makes the study of this region inaccessible by the\nnext generation experiments. But there is an allowed region of m$_0$ (7-30 meV)\nin the framework of NO, where the predicted values for $\\langle m_{\\nu}\n\\rangle$ could be $\\sim$ 10-30 meV and that is quite achievable for the next\ngeneration experiments. The possibility to rich in the future sensitivity to\n$\\langle m_{\\nu} \\rangle$ at the level of $\\sim$ 1-10 meV is also discussed.", + "category": "nucl-ex" + }, + { + "text": "Measurements of nuclear $\u03b3$-ray line emission in interactions of\n protons and $\u03b1$ particles with N, O, Ne and Si: $\\gamma$-ray production cross sections have been measured in proton\nirradiations of N, Ne and Si and $\\alpha$-particle irradiations of N and Ne. In\nthe same experiment we extracted also line shapes for strong $\\gamma$-ray lines\nof $^{16}$O produced in proton and $\\alpha$-particle irradiations of O. For the\nmeasurements gas targets were used for N, O and Ne and a thick foil was used\nfor Si. All targets were of natural isotopic composition. Beams in the energy\nrange up to 26 MeV for protons and 39 MeV for $\\alpha$-particles have been\ndelivered by the IPN-Orsay tandem accelerator. The $\\gamma$ rays have been\ndetected with four HP-Ge detectors in the angular range 30$^{\\circ}$ to\n135$^{\\circ}$. We extracted 36 cross section excitation functions for proton\nreactions and 14 for $\\alpha$-particle reactions. For the majority of the\nexcitation functions no other data exist to our knowledge. Where comparison\nwith existing data was possible usually a very good agreement was found. It is\nshown that these data are very interesting for constraining nuclear reaction\nmodels. In particular the agreement of cross section calculations in the\nnuclear reaction code TALYS with the measured data could be improved by\nadjusting the coupling schemes of collective levels in the target nuclei\n$^{14}$N, $^{20,22}$Ne and $^{28}$Si. The importance of these results for the\nmodeling of nuclear $\\gamma$-ray line emission in astrophysical sites is\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Observation of isotonic symmetry for enhanced quadrupole collectivity in\n neutron-rich 62,64,66Fe isotopes at N=40: The transition rates for the 2_{1}^{+} states in 62,64,66Fe were studied\nusing the Recoil Distance Doppler-Shift technique applied to projectile Coulomb\nexcitation reactions. The deduced E2 strengths illustrate the enhanced\ncollectivity of the neutron-rich Fe isotopes up to N=40. The results are\ninterpreted by the generalized concept of valence proton symmetry which\ndescribes the evolution of nuclear structure around N=40 as governed by the\nnumber of valence protons with respect to Z~30. The deformation suggested by\nthe experimental data is reproduced by state-of-the-art shell calculations with\na new effective interaction developed for the fpgd valence space.", + "category": "nucl-ex" + }, + { + "text": "Tracing a phase transition with fluctuations of the largest fragment\n size: Statistical multifragmentation models and the ALADIN S254 data: A phase transition signature associated with cumulants of the largest\nfragment size distribution has been identified in statistical\nmultifragmentation models and examined in analysis of the ALADIN S254 data on\nfragmentation of neutron-poor and neutron-rich projectiles. Characteristics of\nthe transition point indicated by this signature are weakly dependent on the\nA/Z ratio of the fragmenting spectator source. In particular, chemical\nfreeze-out temperatures are estimated within the range 5.9 to 6.5 MeV. The\nexperimental results are well reproduced by the SMM model.", + "category": "nucl-ex" + }, + { + "text": "Study of the Fusion-Fission Process in the $^{35}Cl+^{24}Mg$ Reaction: Fusion-fission and fully energy-damped binary processes of the\n$^{35}$Cl+$^{24}$Mg reaction were investigated using particle-particle\ncoincidence techniques at a $^{35}$Cl bombarding energy of E$_{lab}$ $\\approx$\n8 MeV/nucleon. Inclusive data were also taken in order to determine the partial\nwave distribution of the fusion process. The fragment-fragment correlation data\nshow that the majority of events arises from a binary-decay process with a\nrelatively large multiplicity of secondary light-charged particles emitted by\nthe two primary excited fragments in the exit channel. No evidence is observed\nfor ternary-breakup processes, as expected from the systematics recently\nestablished for incident energies below 15 MeV/nucleon and for a large number\nof reactions. The binary-process results are compared with predictions of\nstatistical-model calculations. The calculations were performed using the\nExtended Hauser-Feshbach method, based on the available phase space at the\nscission point of the compound nucleus. This new method uses\ntemperature-dependent level densities and its predictions are in good agreement\nwith the presented experimental data, thus consistent with the fusion-fission\norigin of the binary fully-damped yields.", + "category": "nucl-ex" + }, + { + "text": "Exploration of jet energy loss via direct $\u03b3$-charged particle\n azimuthal correlation measurements: The multiplicities of charged particles azimuthally associated with direct\nphotons and $\\pi^{0}$ have been measured for Au+Au, p+p, and d+Au collisions at\n$\\sqrt{s_{NN}}$ = 200 GeV in the STAR experiment. Charged particles with\ntransverse momentum 0.5 $<$ $p_T^{h^{\\pm}}$ $<$ 16 GeV/c for p+p and d+Au, and\n3 $<$ $p_T^{h^{\\pm}}$ $<$ 16 GeV/c for Au+Au and pseudorapidity $\\mid\\eta\\mid$\n$\\leq$ 1.5 in coincidence with direct photons and $\\pi^{0}$ of high transverse\nmomentum 8 $<$ $p_T^{\\gamma,\\pi^{0}}$ $<$ 16 GeV/c at $\\mid\\eta\\mid$ $\\leq$ 0.9\nhave been used for this analysis. Within the considered range of kinematics,\nthe observed suppressions of the associated yields per direct $\\gamma$ in\ncentral Au+Au relative to p+p and d+Au are similar and constant with direct\nphoton fractional energy $z_{T}$ ($z_{T}=p_{T}^{h^{\\pm}}/p_{T}^{\\gamma}$). The\nmeasured suppressions of the associated yields with direct $\\gamma$ are\ncomparable to those with $\\pi^{0}$. The data are compared to theoretical\npredictions.", + "category": "nucl-ex" + }, + { + "text": "Strongly Enhanced Low Energy Alpha-Particle Decay in Heavy Actinide\n Nuclei and Long-Lived Superdeformed and Hyperdeformed Isomeric States: Relatively low energy and very enhanced alpha-particle groups have been\nobserved in various actinide fractions produced via secondary reactions in a\nCERN W target which had been irradiated with 24-GeV protons. In particular,\n5.14, 5.27 and 5.53 MeV alpha-particle groups with corresponding half-lives of\n3.8(+ -)1.0 y, 625(+ -)84 d and 26(+ -)7 d, have been seen in Bk, Es and Lr-No\nsources, respectively. The measured energies are a few MeV lower than the known\ng.s. to g.s. alpha-decays in the corresponding neutron-deficient actinide\nnuclei. The half-lives are 4 to 7 orders of magnitude shorter than expected\nfrom the systematics of alpha-particle decay in this region of nuclei. The\ndeduced evaporation residue cross sections are in the mb region, about 4 orders\nof magnitude higher than expected. A consistent interpretation of the data is\ngiven in terms of production of long-lived isomeric states in the second and\nthird wells of the potential-energy surfaces of the parent nuclei, which decay\nto the corresponding wells in the daughters. The possibility that the isomeric\nstates in the third minimum are actually the true or very near the true ground\nstates of the nuclei, and consequences regarding the production of the\nlong-lived superheavy elements, are discussed.", + "category": "nucl-ex" + }, + { + "text": "Nuclear multifragmentation and phase transition for hot nuclei: This review article is focused on the tremendous progress realized during the\nlast fifteen years in the understanding of multifragmentation and its\nrelationship to the liquid-gas phase diagram of nuclei and nuclear matter. The\nexplosion of the whole nucleus, early predicted by Bohr [N. Bohr, Nature 137\n(1936) 351], is a very complex and rich subject which continues to fascinate\nnuclear physicists as well as theoreticians who extend the thermodynamics of\nphase transitions to finite systems.", + "category": "nucl-ex" + }, + { + "text": "First measurements of spin correlations in the np -> d pi^0 reaction: The transverse spin correlations Axx and Ayy in the np-> d pi^0 reaction have\nbeen measured for the first time in quasi-free kinematics at the COSY-ANKE\nfacility using a polarised deuteron beam incident on a polarised hydrogen cell\ntarget. The results obtained for neutron energies close to 353 MeV and 600 MeV\nare in good agreement with the partial wave analysis of data on the\nisospin-related pp-> d pi^+ reaction, though the present results cover also the\nsmall-angle region, which was largely absent from these data.", + "category": "nucl-ex" + }, + { + "text": "Improved Comparison of Measurements and Calculations of $\\hat{q}L$ via\n transverse momentum broadening in Relativistic Heavy Ion Collisions using\n di-hadron correlations: The renewed interest in analyzing RHIC data on di-hadron correlations as\nprobes of final state transverse momentum broadening as shown at Quark Matter\n2018[1] by theoretical calculations[6] compared to experimental\nmeasurements[4,5] led me to review the quoted theoretical calculations and\nexperimental measurements because the theoretical calculation[6] does not show\nthe PHENIX measurements[4] as published. The above references were checked and\nfits were performed to the published measurements[4,7] to determine $\\hat{q}L$\nfrom the measured azimuthal broadening to compare with the theoretical\ncalculation[6]. The new results will be presented in addition to some\ncorrections to the previous work[3]. The measured values of $\\hat{q}L$ show the\ninteresting effect of being consistent with zero for larger values of\nassociated $p_{Ta}\\geq3$ GeV/c which is shown to be related to well known\nmeasurements of the ratio of the Au+Au to p+p associated $p_{Ta}$ distributions\nfor a given trigger $p_{Tt}$ called $I_{AA}$[23,25]. Di-jets rather than\ndi-hadrons are proposed as an improved azimuthal broadening measurement to\ndetermine $\\hat{q}L$ and possibly $\\hat{q}$.", + "category": "nucl-ex" + }, + { + "text": "Comprehensive evidences of octupole vibration in $^{158}$Gd: Comprehensive evidences of the SU(3) limit in the spdf interacting boson\nmodel, a dynamical symmetry describing octupole vibration in rotational\nnucleus, are found in the spectrum, E2 and E1 transition rates, and relative\nintensities in $^{158}$Gd. This gives a good example of rotational nucleus with\noctupole vibration in rare-earth region.", + "category": "nucl-ex" + }, + { + "text": "Detailed studies of $^{100}$Mo two-neutrino double beta decay in NEMO-3: The full data set of the NEMO-3 experiment has been used to measure the\nhalf-life of the two-neutrino double beta decay of $^{100}$Mo to the ground\nstate of $^{100}$Ru, $T_{1/2} = \\left[ 6.81 \\pm 0.01\\,\\left(\\mbox{stat}\\right)\n^{+0.38}_{-0.40}\\,\\left(\\mbox{syst}\\right) \\right] \\times10^{18}$ y. The\ntwo-electron energy sum, single electron energy spectra and distribution of the\nangle between the electrons are presented with an unprecedented statistics of\n$5\\times10^5$ events and a signal-to-background ratio of ~80. Clear evidence\nfor the Single State Dominance model is found for this nuclear transition.\nLimits on Majoron emitting neutrinoless double beta decay modes with spectral\nindices of n=2,3,7, as well as constraints on Lorentz invariance violation and\non the bosonic neutrino contribution to the two-neutrino double beta decay mode\nare obtained.", + "category": "nucl-ex" + }, + { + "text": "Hard Two-Photon Contribution to Elastic Lepton-Proton Scattering:\n Determined by the OLYMPUS Experiment: The OLYMPUS collaboration reports on a precision measurement of the\npositron-proton to electron-proton elastic cross section ratio, $R_{2\\gamma}$,\na direct measure of the contribution of hard two-photon exchange to the elastic\ncross section. In the OLYMPUS measurement, 2.01~GeV electron and positron beams\nwere directed through a hydrogen gas target internal to the DORIS storage ring\nat DESY. A toroidal magnetic spectrometer instrumented with drift chambers and\ntime-of-flight scintillators detected elastically scattered leptons in\ncoincidence with recoiling protons over a scattering angle range of $\\approx\n20\\degree$ to $80\\degree$. The relative luminosity between the two beam species\nwas monitored using tracking telescopes of interleaved GEM and MWPC detectors\nat $12\\degree$, as well as symmetric M{\\o}ller/Bhabha calorimeters at\n$1.29\\degree$. A total integrated luminosity of 4.5~fb$^{-1}$ was collected. In\nthe extraction of $R_{2\\gamma}$, radiative effects were taken into account\nusing a Monte Carlo generator to simulate the convolutions of internal\nbremsstrahlung with experiment-specific conditions such as detector acceptance\nand reconstruction efficiency. The resulting values of $R_{2\\gamma}$, presented\nhere for a wide range of virtual photon polarization $0.456<\\epsilon<0.978$,\nare smaller than some hadronic two-photon exchange calculations predict, but\nare in reasonable agreement with a subtracted dispersion model and a\nphenomenological fit to the form factor data.", + "category": "nucl-ex" + }, + { + "text": "Identified Particle Elliptic Flow in Au+Au Collisions at\n $\\sqrt{s_{_{NN}}}=130$ GeV}: We report first results on elliptic flow of identified particles at\nmid-rapidity in Au+Au collisions at $\\sqrt{s_{_{NN}}}=130$ GeV using the STAR\nTPC at RHIC. The elliptic flow as a function of transverse momentum and\ncentrality differs significantly for particles of different masses. This\ndependence can be accounted for in hydrodynamic models, indicating that the\nsystem created shows a behavior consistent with collective hydrodynamical flow.\nThe fit to the data with a simple model gives information on the temperature\nand flow velocities at freeze-out.", + "category": "nucl-ex" + }, + { + "text": "Neutron to Mirror-Neutron Oscillations in the Presence of Mirror\n Magnetic Fields: We performed ultracold neutron (UCN) storage measurements to search for\nadditional losses due to neutron (n) to mirror-neutron (n') oscillations as a\nfunction of an applied magnetic field B. In the presence of a mirror magnetic\nfield B', UCN losses would be maximal for B = B'. We did not observe any\nindication for nn' oscillations and placed a lower limit on the oscillation\ntime of tau_{nn'} > 12.0 s at 95% C.L. for any B' between 0 and 12.5 uT.", + "category": "nucl-ex" + }, + { + "text": "Probing the effects of strong electromagnetic fields with\n charge-dependent directed flow in Pb-Pb collisions at the LHC: The first measurement at the LHC of charge-dependent directed flow ($v_{1}$)\nrelative to the spectator plane is presented for Pb-Pb collisions at\n$\\sqrt{s_{\\rm NN}}$ = 5.02 TeV. Results are reported for charged hadrons and\n$\\rm D^{0}$ mesons for the transverse momentum intervals $p_{\\rm T}>0.2$\nGeV/$c$ and $31.5$ GeV/$c$, the data diverges from {\\sc ampt} calculations of $v_2$\nrelative to the initial geometry, indicating the possible dominance of\nnongeometry related correlations, referred to as nonflow. We also present\nmeasurements of the charged-particle multiplicity ($dN_{\\rm ch}/d\\eta$) as a\nfunction of $\\eta$ in central $d$$+$Au collisions at the same energies. We find\nthat in $d$$+$Au collisions at $\\sqrt{s_{_{NN}}}=$200 GeV the $v_2$ scales with\n$dN_{\\rm ch}/d\\eta$ over all $\\eta$ in the PHENIX acceptance. At\n$\\sqrt{s_{_{NN}}}=$62.4, and 39 GeV, $v_2$ scales with $dN_{\\rm ch}/d\\eta$ at\nmidrapidity and forward rapidity, but falls off at backward rapidity. This\ndeparture from the $dN_{\\rm ch}/d\\eta$ scaling may be a further indication of\nnonflow effects dominating at backward rapidity.", + "category": "nucl-ex" + }, + { + "text": "Reaction mechanisms in the 6Li+59Co system: The reactions induced by the weakly bound 6Li projectile interacting with the\nintermediate mass target 59Co were investigated. Light charged particles\nsingles and $\\alpha$-$d$ coincidence measurements were performed at the near\nbarrier energies E_lab = 17.4, 21.5, 25.5 and 29.6 MeV. The main contributions\nof the different competing mechanisms are discussed. A statistical model\nanalysis, Continuum-Discretized Coupled-Channels calculations and two-body\nkinematics were used as tools to provide information to disentangle the main\ncomponents of these mechanisms. A significant contribution of the direct\nbreakup was observed through the difference between the experimental sequential\nbreakup cross section and the CDCC prediction for the non-capture breakup cross\nsection.", + "category": "nucl-ex" + }, + { + "text": "Determination of the Charged Pion Form Factor at Q2=1.60 and 2.45\n (GeV/c)2: The H(e,e'pi+)n cross section was measured at four-momentum transfers of\nQ2=1.60 and 2.45 GeV2 at an invariant mass of the photon nucleon system of\nW=2.22 GeV. The charged pion form factor (F_pi) was extracted from the data by\ncomparing the separated longitudinal pion electroproduction cross section to a\nRegge model prediction in which F_pi is a free parameter. The results indicate\nthat the pion form factor deviates from the charge-radius constrained monopole\nform at these values of Q2 by one sigma, but is still far from its perturbative\nQuantum Chromo-Dynamics prediction.", + "category": "nucl-ex" + }, + { + "text": "Bimodality and Latent Heat of Gold Nuclei: Peripheral collisions give access to a set of events where hot\nquasi-projectile (QP) sources are produced exploring a large range of\nexcitation energy. In this range evaporation and multifragmentation are both\nobserved for a similar charge/size of the sources. In this work, this\nexperimental fact will be described in terms of coexistence of two classes of\nevents in the first order phase transition formalism. For this, a detailed\nstudy of the experimental correlation between the size/charge of the biggest\ncluster/fragment (Z1) and the excitation energy (E*) is made. Making the\nparallel with the same correlation derived from the canonical ensemble\ndescription, a first value of the latent heat and boundaries of spinodal and\ncoexistence zone are extracted.", + "category": "nucl-ex" + }, + { + "text": "Proton and Antiproton Distributions at Mid-Rapidity in Proton-Nucleus\n and Sulphur-Nucleus Collisions: Experiment NA44 has measured proton and antiproton distributions at\nmid-rapidity in sulphur and proton collisions with nuclear targets at 200 and\n450 GeV/c per nucleon respectively. The inverse slopes of transverse mass\ndistributions increase with system size for both protons and antiprotons but\nare slightly lower for antiprotons. this could happen if antiprotons are\nannihilated in the nuclear medium. The antiproton yield increases with system\nsize and centrality and is largest at mid-rapdity. The proton yield also\nincreases with system size and centrality, but decreases from backward rapidity\nto midrapidity. The stopping of protons at these energies lies between the full\nstopping and nuclear transparency scenarios. The data are in reasonable\nagreement with RQMD predictions except for the antiproton yields from\nsulphur-nucleus collisions. PACS numbers 25.75.-q 13.85.-t 13.60.Rj", + "category": "nucl-ex" + }, + { + "text": "Pion and Kaon Structure at the Electron-Ion Collider: Understanding the origin and dynamics of hadron structure and in turn that of\natomic nuclei is a central goal of nuclear physics. This challenge entails the\nquestions of how does the roughly 1 GeV mass-scale that characterizes atomic\nnuclei appear; why does it have the observed value; and, enigmatically, why are\nthe composite Nambu-Goldstone (NG) bosons in quantum chromodynamics (QCD)\nabnormally light in comparison? In this perspective, we provide an analysis of\nthe mass budget of the pion and proton in QCD; discuss the special role of the\nkaon, which lies near the boundary between dominance of strong and Higgs\nmass-generation mechanisms; and explain the need for a coherent effort in QCD\nphenomenology and continuum calculations, in exa-scale computing as provided by\nlattice QCD, and in experiments to make progress in understanding the origins\nof hadron masses and the distribution of that mass within them. We compare the\nunique capabilities foreseen at the electron-ion collider (EIC) with those at\nthe hadron-electron ring accelerator (HERA), the only previous electron-proton\ncollider; and describe five key experimental measurements, enabled by the EIC\nand aimed at delivering fundamental insights that will generate concrete\nanswers to the questions of how mass and structure arise in the pion and kaon,\nthe Standard Model's NG modes, whose surprisingly low mass is critical to the\nevolution of our Universe.", + "category": "nucl-ex" + }, + { + "text": "Differential cross sections and spin density matrix elements for the\n reaction gamma p -> p omega: High-statistics differential cross sections and spin density matrix elements\nfor the reaction gamma p -> p omega have been measured using the CLAS at\nJefferson Lab for center-of-mass (CM) energies from threshold up to 2.84 GeV.\nResults are reported in 112 10-MeV wide CM energy bins, each subdivided into\ncos(theta_CM) bins of width 0.1. These are the most precise and extensive omega\nphotoproduction measurements to date. A number of prominent structures are\nclearly present in the data. Many of these have not previously been observed\ndue to limited statistics in earlier measurements.", + "category": "nucl-ex" + }, + { + "text": "Ground and excited quarkonium states as probes of MPI in small systems\n with ALICE: Quarkonia represent excellent tools for understanding the role of multiparton\ninteractions (MPI) in small systems, i.e., pp and p-A collisions. Probing MPI\nwith quarkonia can be done directly by looking at quarkonium associated\nproduction, or indirectly by studying the multiplicity dependence of quarkonium\nproduction. In these proceedings, the results from the ALICE experiment on\ndirect and indirect MPI probes are discussed. The self-normalized yields of\ncharmonium production as a function of the charged-particle multiplicity in pp\nand p--Pb collisions at \\sqrt{s} = 13 TeV and \\sqrt{s_{NN} = 8.16 TeV,\nrespectively, are discussed. Additionally, the corresponding measurements of\nthe charmonium self-normalized excited-to-ground state ratio as a function of\nthe charged-particle multiplicity are reported. The new measurement of the\ndouble J/\\psi production at forward rapidity in pp collisions at \\sqrt{s} = 13\nTeV TeV is presented. Finally, the multiplicity dependence of the bottomonium\nproduction in pp collisions at \\sqrt{s} = 13 TeV is discussed. The comparison\nto the available theoretical calculations is reported.", + "category": "nucl-ex" + }, + { + "text": "Recoil-alpha-fission and recoil-alpha-alpha-fission events observed in\n the reaction Ca-48 + Am-243: Products of the fusion-evaporation reaction Ca-48 + Am-243 were studied with\nthe TASISpec set-up at the gas-filled separator TASCA at the GSI\nHelmholtzzentrum f\\\"ur Schwerionenforschung. Amongst the detected thirty\ncorrelated alpha-decay chains associated with the production of element Z=115,\ntwo recoil-alpha-fission and five recoil-alpha-alpha-fission events were\nobserved. The latter are similar to four such events reported from experiments\nperformed at the Dubna gas-filled separator. Contrary to their interpretation,\nwe propose an alternative view, namely to assign eight of these eleven decay\nchains of recoil-alpha(-alpha)-fission type to start from the 3n-evaporation\nchannel 115-288. The other three decay chains remain viable candidates for the\n2n-evaporation channel 115-289.", + "category": "nucl-ex" + }, + { + "text": "Calculation of light nucleus reaction cross sections in Geant4: Total reaction cross sections of light projectile nucleus (H-2, H-3, He-3 and\nHe-4) interactions with nuclei are calculated using Geant4 models, and compared\nwith experimental data. It is shown that the models give various predictions at\nlow energies, in the region of the Coulomb barrier. \"Shen model\" (W.-Q. Shen et\nal., Nucl. Phys. {\\bf A491} (1989) 130) is identified as an improvement over\nother models.", + "category": "nucl-ex" + }, + { + "text": "Direct determination of the atomic mass difference of the pairs\n $^{76}$As-$^{76}$Se and $^{155}$Tb-$^{155}$Gd rules out $^{76}$As and\n $^{155}$Tb as possible candidates for electron (anti)neutrino mass\n measurements: The first direct determination of the ground-state-to-ground-state $Q$ values\nof the $\\beta^-$ decay $^{76}$As $\\rightarrow$ $^{76}$Se and the\nelectron-capture decay $^{155}$Tb $\\rightarrow$ $^{155}$Gd was performed\nutilizing the double Penning trap mass spectrometer JYFLTRAP. By measuring the\natomic mass difference of the decay pairs via the phase-imaging\nion-cyclotron-resonance (PI-ICR) technique, the $Q$ values of $^{76}$As\n$\\rightarrow$ $^{76}$Se and $^{155}$Tb $\\rightarrow$ $^{155}$Gd were determined\nto be 2959.265(74) keV and 814.94(18) keV, respectively. The precision was\nincreased relative to earlier measurements by factors of 12 and 57,\nrespectively. The new $Q$ values are 1.33 keV and 5 keV lower compared to the\nvalues adopted in the most recent Atomic Mass Evaluation 2020. With the newly\ndetermined ground-state-to-ground-state $Q$ values combined with the excitation\nenergy from $\\gamma$-ray spectroscopy, the $Q$ values for\nground-state-to-excited-state transitions $^{76}$As (ground state)\n$\\rightarrow$ $^{76}$Se$^*$ (2968.4(7) keV) and $^{155}$Tb (ground state)\n$\\rightarrow$ $^{155}$Gd$^*$ (815.731(3) keV) were derived to be -9.13(70) keV\nand -0.79(18) keV. Thus we have confirmed that both of the $\\beta^{-}$-decay\nand EC-decay candidate transitions are energetically forbidden at a level of at\nleast 4$\\sigma$, thus definitely excluding these two cases from the list of\npotential candidates for the search of low-$Q$-value $\\beta^-$ or EC decays to\ndetermine the electron-(anti)neutrino mass.", + "category": "nucl-ex" + }, + { + "text": "Searching for Hybrid Mesons with GlueX: Hybrid mesons consist of a quark-antiquark pair bound together by a gluonic\nfield that is in an excited state. Measuring the spectrum of these states will\nprovide valuable information on the gluonic degrees of freedom of QCD in the\nquark-confinement regime.\n A rich spectrum of hybrid meson states has been predicted, but only a few\nexperiments have reported evidence of their existence. The GlueX experiment at\nJefferson Lab is designed to search for and measure the spectrum of light-mass\nhybrid mesons, and it has began its physics run in Spring 2017. For the\nexperiment, a 12 GeV electron beam incident on a diamond radiator is used to\nproduce a linearly-polarized, coherent bremsstrahlung tagged-photon beam with a\ncoherent peak at 9 GeV. The linearly-polarized photon beam is incident on a\nproton target located within the hermetic GlueX detector, which can detect many\ndifferent final states to which the hybrid mesons are predicted to decay.\nMeasurements with these initial data are discussed, including beam asymmetry\nmeasurements, the search for photoproduced $\\Xi$ baryons, and near-threshold\ncharm production.", + "category": "nucl-ex" + }, + { + "text": "Recent results from the strong interactions program of NA61/SHINE: The NA61/SHINE experiment studies hadron production in hadron+hadron,\nhadron+nucleus and nucleus+nucleus collisions. The strong interactions program\nhas two main purposes: study the properties of the onset of deconfinement and\nsearch for the signatures of the critical point of strongly interacting matter.\nThis aim is pursued by performing a two-dimensional scan of the phase diagram\nby varying the energy/momentum (13A-158A GeV/c) and the system size (p+p,\nBe+Be, Ar+Sc, Xe+La) of the collisions. This publication reviews recent results\nfrom p+p, Be+Be and Ar+Sc interactions. Measured particle spectra are discussed\nand compared to NA49 results from Pb+Pb collisions. The results illustrate the\nprogress towards scanning the phase diagram of strongly interacting matter.", + "category": "nucl-ex" + }, + { + "text": "Linear polarization-direction correlations in $\u03b3$-ray scattering\n experiments: Scattering measurements with incident linearly polarized $\\gamma$ rays\nprovide information on spins, parities, and $\\gamma$-ray multipolarity mixing\ncoefficients, and, therefore, on the nuclear matrix elements involved in the\ntransitions. We present the general formalism for analyzing the observed\nangular correlations. The expressions are used to compute three-dimensional\nradiation patterns, which are important tools for optimizing experimental\nsetups. Frequently, $\\gamma$-ray transitions can proceed via two\nmultipolarities that mix coherently. In such cases, the relative phases of the\nnuclear matrix elements are important when comparing results from different\nmeasurements. We discuss different phase conventions that have been used in the\nliterature and present their relationships. Finally, we propose a basic\nexperimental geometry consisting of detectors located at four different spatial\nlocations. For this geometry, we present the measured anisotropies of the\nemitted $\\gamma$ rays in graphical format as an aid in the data analysis.", + "category": "nucl-ex" + }, + { + "text": "Measurement of hadron suppression and study of its connection with\n vanishing $v_{\\mathrm{3}}$ at low $\\sqrt{s_{\\mathrm{NN}}}$ in Au+Au\n collisions with STAR: At top RHIC and LHC energies the suppression of high transverse momentum\n($p_{\\mathrm{T}}$) hadrons provides evidence for partonic energy loss in QGP.\nWe study partonic energy loss in the RHIC Beam Energy Scan (BES) by\ninvestigating the centrality dependence of the binary-collision-scaled\nhigh-$p_{\\mathrm{T}}$ yields. Observing a decrease of the scaled yield in more\ncentral collisions is proposed as a possible signature for jet quenching. Even\nat energies and centralities where this signature is lost a QGP may still be\nformed since competing phenomena responsible for enhancements may overwhelm the\nsuppression from energy loss. Measurements in several ranges of\n$p_{\\mathrm{T}}$ from $\\sqrt{s_{_{\\mathrm{NN}}}}$ = 7.7, 11.5, 14.5, 19.6, 27,\n39, 62.4, and 200 GeV data show that relative hadron suppression persists at\nleast down to 14.5 GeV.\n To further investigate both the possible formation of a QGP at these lower\nenergies and whether the observed hadron suppression coincides with the onset\nof other QGP signatures, we examine the energy and centrality dependence of\n$v_{3}$. Models have shown that the development of $v_{3}$ requires the\npresence of a low viscosity phase early in the collision. We find that for\ncollisions with $N_{\\mathrm{part}}$<50, $v_{3}$ disappears for energies below\n14.5 GeV, suggestive of a turn-off of the QGP. But for $N_{\\mathrm{part}}$>50,\n$v_{3}$ persists down to the lowest energies. Together, these signatures\nprovide possible evidence for the formation of a QGP in the lowest energy\ncollisions at RHIC.", + "category": "nucl-ex" + }, + { + "text": "Neutrons from multifragmentation reactions: The neutron emission in the fragmentation of stable and radioactive Sn and La\nprojectiles of 600 MeV per nucleon has been studied with the Large Neutron\nDetector LAND coupled to the ALADIN forward spectrometer at SIS. A\ncluster-recognition algorithm is used to identify individual particles within\nthe hit distributions registered with LAND. The obtained momentum distributions\nare extrapolated over the full phase space occupied by the neutrons from the\nprojectile-spectator source. The mean multiplicities of spectator neutrons\nreach values of up to 12 and depend strongly on the isotopic composition of the\nprojectile. An effective source temperature of T approx. 3 - 4 MeV is deduced\nfrom the transverse momentum distributions.\n For the interpretation of the data, calculations with the Statistical\nMultifragmentation Model for a properly chosen ensemble of excited sources were\nperformed. The possible modification of the liquid-drop parameters of the\nfragment description in the hot environment is studied, and a significant\nreduction of the symmetry-term coefficient is found necessary to simultaneously\nreproduce the neutron multiplicities and the mean neutron-to-proton ratios\n/Z of Z <= 10 fragments. Because of the similarity of the freeze-out\nconditions with those encountered in supernova scenarios, this is of\nastrophysical interest.", + "category": "nucl-ex" + }, + { + "text": "D^0 measurements in Au+Au Collisions at \\sqrt{s_{NN}} = 200 GeV using\n the STAR Silicon Inner Tracker: We present preliminary results from D^0 meson measurements through the\nhadronic decay channel in minimum bias Au+Au collisions at \\sqrt{s_{NN}} = 200\nGeV at STAR. The measurements are performed using a secondary vertexing\ntechnique that exploits the resolution given by the Silicon detectors available\nin STAR.", + "category": "nucl-ex" + }, + { + "text": "Scaling Characteristics of Azimuthal Anisotropy at RHIC: Recent differential measurements of elliptic flow are used to probe several\nhydrodynamic scaling predictions. Eccentricity scaling is observed for Cu+Cu\nand Au+Au collisions at $\\sqrt{s_{NN}}=~200$ GeV, suggesting essentially\ncomplete thermalization of the high energy density matter produced in these\ncollisions. An estimate of the speed of sound is also obtained from the\neccentricity scaled elliptic flow. The predicted mass scaling is observed for\nparticles with transverse kinetic energy KE$_T$ up to $\\sim 1$ GeV. For KE$_T$\nvalues above $\\sim 1$ GeV, valence quark number scaling compatible with\npartonic degrees of freedom is observed.", + "category": "nucl-ex" + }, + { + "text": "High precision probe of the fully sequential decay width of the Hoyle\n state in $^{12}$C: The decay path of the Hoyle state in $^{12}$C ($E_x=7.654\\textrm{MeV}$) has\nbeen studied with the\n$^{14}\\textrm{N}(\\textrm{d},\\alpha_2)^{12}\\textrm{C}(7.654)$ reaction induced\nat $10.5\\textrm{MeV}$. High resolution invariant mass spectroscopy techniques\nhave allowed to unambiguously disentangle direct and sequential decays of the\nstate passing through the ground state of $^{8}$Be. Thanks to the almost total\nabsence of background and the attained resolution, a fully sequential decay\ncontribution to the width of the state has been observed. The direct decay\nwidth is negligible, with an upper limit of $0.043\\%$ ($95\\%$ C.L.). The\nprecision of this result is about a factor $5$ higher than previous studies.\nThis has significant implications on nuclear structure, as it provides\nconstraints to $3$-$\\alpha$ cluster model calculations, where higher precision\nlimits are needed.", + "category": "nucl-ex" + }, + { + "text": "Extraction of jet topology using three particle correlations: Recent theoretical studies have indicated that the topological features of\naway-side jet fragments can be significantly altered by medium-induced\nmodifications. The leading candidates resulting from such modifications are\nMach Cones and deflected jets. We show that three particle correlations are\nable to distinguish between these different modification scenarios. Initial\nresults from an application of the method to Au+Au collisions at RHIC\n($\\sqrt{s_{NN}}=200$ GeV) are presented.", + "category": "nucl-ex" + }, + { + "text": "Observation of a structure in the M$_{p\u03b7}$ invariant mass\n distribution near 1700 MeV/$c^2$ in the $\\mathbf{\u03b3p \\rightarrow p \u03c0^0\n \u03b7} $ reaction: The reaction $\\gamma p \\rightarrow p \\pi^0 \\eta$ has been studied with the\nCBELSA/TAPS detector at the electron stretcher accelerator ELSA in Bonn for\nincident photon energies from threshold up to 3.1 GeV. This paper has been\nmotivated by the recently claimed observation of a narrow structure in the\nM$_{N\\eta}$ invariant mass distribution at a mass of 1678 MeV/$c^2$. The\nexistence of this structure cannot be confirmed in the present work. Instead,\nfor E$_{\\gamma}$ = 1400 - 1500 MeV and the cut M$_{p\\pi^0} \\le 1190 $ MeV/$c^2$\na statistically significant structure in the M$_{p\\eta}$ invariant mass\ndistribution near 1700 MeV/$c^2$ is observed with a width of $\\Gamma\\approx 35$\nMeV/$c^2$ while the mass resolution is $\\sigma_{res}$ = 5 MeV/$c^2$. Increasing\nthe incident photon energy from 1420 to 1540 MeV this structure shifts in mass\nfrom $\\approx$ 1700MeV/c$^2$ to $\\approx$ 1725 MeV/$c^2$; the width increases\nto about 50 MeV/$c^2$ and decreases thereafter. The cross section associated\nwith this structure reaches a maximum of $\\approx$ 100 nb around E$_{\\gamma}\n\\approx$ 1490 MeV (W $\\approx $ 1920 MeV), which coincides with the $p a_0$\nthreshold. Three scenarios are discussed which might be the origin of this\nstructure in the M$_{p\\eta}$ invariant mass distribution. The most likely\ninterpretation is that it is due to a triangular singularity in the $\\gamma p\n\\rightarrow p a_0 \\rightarrow p \\pi^0 \\eta$ reaction", + "category": "nucl-ex" + }, + { + "text": "Study of elastic and inelastic scattering of $^7$Be + $^{12}$C at 35 MeV: The elastic and inelastic scattering of $^7$Be from $^{12}$C have been\nmeasured at an incident energy of 35 MeV. The inelastic scattering leading to\nthe 4.439 MeV excited state of $^{12}$C has been measured for the first time.\nThe experimental data cover an angular range of $\\theta_{cm}$ =\n15$^{\\circ}$-120$^{\\circ}$. Optical model analyses were carried out with\nWoods-Saxon and double-folding potential using the density dependent M3Y\n(DDM3Y) effective interaction. The microscopic analysis of the elastic data\nindicates breakup channel coupling effect. A coupled-channel analysis of the\ninelastic scattering, based on collective form factors, show that mutual\nexcitation of both $^7$Be and $^{12}$C is significantly smaller than the single\nexcitation of $^{12}$C. The larger deformation length obtained from the DWBA\nanalysis could be explained by including the excitation of $^7$Be in a\ncoupled-channel analysis. The breakup cross section of $^7$Be is estimated to\nbe less than 10$\\%$ of the reaction cross section. The intrinsic deformation\nlength obtained for the $^{12}$C$^*$ (4.439 MeV) state is $\\delta _2$ = 1.37\nfm. The total reaction cross section deduced from the analysis agrees very well\nwith Wong's calculations for similar weakly bound light nuclei on $^{12}$C\ntarget.", + "category": "nucl-ex" + }, + { + "text": "A Hadron Blind Detector for the PHENIX Experiment: A novel Hadron Blind Detector (HBD) has been developed for an upgrade of the\nPHENIX experiment at RHIC. The HBD will allow a precise measurement of\nelectron-positron pairs from the decay of the light vector mesons and the\nlow-mass pair continuum in heavy-ion collisions. The detector consists of a 50\ncm long radiator filled with pure CF4 and directly coupled in a windowless\nconfiguration to a triple Gas Electron Multiplier (GEM) detector with a CsI\nphotocathode evaporated on the top face of the first GEM foil.", + "category": "nucl-ex" + }, + { + "text": "Isotopic effects in multifragmentation and the nuclear equation of state: Isotopic effects in spectator fragmentations following heavy-ion collisions\nat relativistic energies are investigated using data from recent exclusive\nexperiments with SIS beams at GSI. Reactions of 12C on 112,124Sn at incident\nenergies 300 and 600 MeV per nucleon were studied with the INDRA multidetector\nwhile the fragmentation of stable 124Sn and radioactive 107Sn and 124La\nprojectiles was studied with the ALADIN spectrometer.\n The global characteristics of the reactions are very similar. This includes\nthe rise and fall of fragment production and deduced observables as, e.g., the\nbreakup temperature obtained from double ratios of isotope yields. The mass\ndistributions depend strongly on the neutron-to-proton ratio of the decaying\nsystem, as expected for a simultaneous statistical breakup. The ratios of\nlight-isotope yields from neutron-rich and neutron-poor systems follow the law\nof isoscaling. The deduced scaling parameters decrease strongly with increasing\ncentrality to values smaller than 50% of those obtained for the peripheral\nevent groups. This is not compensated by an equivalent rise of the breakup\ntemperatures which suggests a reduction of the symmetry term required in a\nliquid-drop description of the fragments at freeze-out.", + "category": "nucl-ex" + }, + { + "text": "A Detailed Analysis and Monte Carlo Simulation of the Neutron Lifetime\n Experiment S. Arzumanov et al., Phys. Lett. B 483 (2000) 15: We performed a detailed analysis and the Monte Carlo simulation of the\nneutron lifetime experiment [S. Arzumanov et al., Phys. Lett. B 483 (2000) 15]\nbecause of the strong disagreement by 5.6 standard deviations between the\nresults of this experiment and our experiment [A. Serebrov et al., Phys. Lett.\nB 605 (2005) 72]. We found a few effects which were not taken into account in\nthe experiment [S. Arzumanov et al., Phys. Lett. B 483 (2000) 15]. The possible\ncorrection is -5.5 s with uncertainty of 2.4 s which comes from initial data\nknowledge. We assume that after taking into account this correction the result\nof work [S. Arzumanov et al., Phys. Lett. B 483 (2000) 15] for neutron lifetime\n885.4 +/- 0.9stat +/- 0.4syst s could be corrected to 879.9 +/- 0.9stat +/-\n2.4syst s.", + "category": "nucl-ex" + }, + { + "text": "Open heavy flavour reconstruction in the ALICE central barrel: The ALICE experiment will be able to detect open charm and beauty hadrons in\nproton-proton and heavy ion collisions in the new energy regime of the CERN\nLarge Hadron Collider (LHC). Heavy flavours are a powerful tool to investigate\nthe medium created in high energy nucleus--nucleus interactions because they\nare produced in the hard scatterings occurring at early times and, thanks to\ntheir long lifetime on the collision timescale, they probe all the stages of\nthe system evolution. The detectors of the ALICE central barrel ($-0.9 < \\eta <\n0.9$) will allow to track charged particles down to low transverse momentum\n($\\approx$ 100 MeV/$c$) and will provide hadron and electron identification as\nwell as an accurate measurement of the positions of primary and secondary\nvertices. It will therefore be possible to measure the production of open heavy\nflavours in the central rapidity region down to low transverse momentum,\nexploiting the semi-electronic and the hadronic decay channels. Here we present\na general overview of the ALICE perspectives for heavy flavour physics and some\nexamples from the open charm and beauty analyses which have been developed and\ntested on detailed simulations of the experimental apparatus.", + "category": "nucl-ex" + }, + { + "text": "Recent results from the NA61/SHINE strong interaction physics programme: The main physics goals of the NA61/SHINE programme on strong interactions are\nthe study of the properties of the onset of deconfinement and the search for\nsignatures of the critical point of strongly interacting matter. For this\npurpose a scan of the two dimensional phase diagram ($T$-$\\mu_{B}$) is being\nperformed at the SPS by measurements of hadron production in nucleus-nucleus\ncollisions as a function of collision energy and system size.\n This contribution presents intriguing results on the energy dependence of\nhadron spectra and yields in inelastic p+p and centrality selected Be+Be and\nAr+Sc collisions. In particular, the energy dependence of the signals of\ndeconfinement, the \"horn\", \"step\" and \"kink\", and new results on fluctuations\nand correlations are shown and compared with the corresponding data of other\nexperiments and model predictions.", + "category": "nucl-ex" + }, + { + "text": "Investigation of the $\\mathbf{\u03a3^{0}}$ Production Mechanism in p(3.5\n GeV)+p Collisions: The production of $\\Sigma^0$ hyperons in proton proton collisions at a beam\nkinetic energy of 3.5 GeV impinging on a liquid hydrogen target was\ninvestigated using data collected with the HADES setup. The total production\ncross section is found to be $\\mathrm{\\sigma (pK^{+}\\Sigma^{0}) [\\mu b] = 17.7\n\\pm 1.7 (stat) \\pm 1.6 (syst)}$. Differential cross section distributions of\nthe exclusive channel $\\mathrm{pp \\rightarrow pK^{+}\\Sigma^{0}}$ were analyzed\nin the center-of-mass, Gottfried-Jackson and helicity reference frames for the\nfirst time at the excess energy of 556 MeV. The data support the interplay\nbetween pion and kaon exchange mechanisms and clearly demonstrate the\ncontribution of interfering nucleon resonances decaying to\n$\\mathrm{K^{+}\\Sigma^{0}}$. The Bonn-Gatchina partial wave analysis was\nemployed to analyse the data. Due to the limited statistics, it was not\npossible to obtain an unambiguous determination of the relative contribution of\nintermediate nucleon resonances to the final state. However nucleon resonances\nwith masses around 1.710 $\\mathrm{GeV/c^{2}}$ ($\\mathrm{N^{*}(1710)}$) and\n1.900 $\\mathrm{GeV/c^{2}}$ ($\\mathrm{N^{*}(1900)}$ or\n$\\mathrm{\\Delta^{*}(1900)}$) are preferred by the fit.", + "category": "nucl-ex" + }, + { + "text": "First observation of in-medium modifications of the omega meson: The photoproduction of omega mesons on nuclei has been investigated using the\nCrystal Barrel/TAPS experiment at the ELSA tagged photon facility in Bonn. The\naim is to study possible in-medium modifications of the omega meson via the\nreaction A(gamma, omega)X. Results obtained for Nb are compared to a reference\nmeasurement on a liquid hydrogen target. While for recoiling, long-lived mesons\n(pi, eta and etaprime), which decay outside of the nucleus, a difference in the\nlineshape for the two data samples is not observed, we find a significant\nenhancement towards lower masses for omega mesons with low momenta produced on\nthe Nb target.", + "category": "nucl-ex" + }, + { + "text": "The behaviour of constrained caloric curves as ultimate signature of a\n phase transition for hot nuclei: Simulations based on experimental data obtained from multifragmenting\nquasifused nuclei produced in central 129Xe + natSn collisions have been used\nto deduce event by event freeze-out properties on the thermal excitation energy\nrange 4-12 AMeV. From these properties and temperatures deduced from proton\ntransverse momentum fluctuations constrained caloric curves have been built. At\nconstant average volumes caloric curves exhibit a monotonous behaviour whereas\nfor constrained pressures a backbending is observed. Such results support the\nexistence of a first order phase transition for hot nuclei.", + "category": "nucl-ex" + }, + { + "text": "High precision half-life measurement of $^{125}$Cs and $^{125}$Xe with\n \u03b3-spectroscopy: In order to provide data for the simulation of the astrophysical\n$\\gamma$-process, the cross section measurement of the\n$^{124}$Xe(p,$\\gamma$)$^{125}$Cs reaction is in progress at MTA Atomki using\nthe activation technique. Precise information on the decay characteristics of\nthe reaction products is of crucial importance for measurements carried out\nusing this method. The half-lives of the produced $^{125}$Cs and its daughter\n$^{125}$Xe are published in previous works, but with large uncertainties and\nambiguous values. To make these nuclear parameters more precise, the half-lives\nhave been re-measured with high precision using $\\gamma$-spectroscopy. The\nobtained new half-life values are t$_{1/2}$ = 44.35 $\\pm$ 0.29 minutes for\n$^{125}$Cs and t$_{1/2}$ = 16.87 $\\pm$ 0.08 hours for $^{125}$Xe.", + "category": "nucl-ex" + }, + { + "text": "Wanted! Nuclear Data for Dark Matter Astrophysics: Astronomical observations from small galaxies to the largest scales in the\nuniverse can be consistently explained by the simple idea of dark matter. The\nnature of dark matter is however still unknown. Empirically it cannot be any of\nthe known particles, and many theories postulate it as a new elementary\nparticle. Searches for dark matter particles are under way: production at\nhigh-energy accelerators, direct detection through dark matter-nucleus\nscattering, indirect detection through cosmic rays, gamma rays, or effects on\nstars. Particle dark matter searches rely on observing an excess of events\nabove background, and a lot of controversies have arisen over the origin of\nobserved excesses. With the new high-quality cosmic ray measurements from the\nAMS-02 experiment, the major uncertainty in modeling cosmic ray fluxes is in\nthe nuclear physics cross sections for spallation and fragmentation of cosmic\nrays off interstellar hydrogen and helium. The understanding of direct\ndetection backgrounds is limited by poor knowledge of cosmic ray activation in\ndetector materials, with order of magnitude differences between simulation\ncodes. A scarcity of data on nucleon spin densities blurs the connection\nbetween dark matter theory and experiments. What is needed, ideally, are more\nand better measurements of spallation cross sections relevant to cosmic rays\nand cosmogenic activation, and data on the nucleon spin densities in nuclei.", + "category": "nucl-ex" + }, + { + "text": "Inclusive J/$\u03c8$ and $\u03c8$(2S) production in pp and p-Pb collisions\n at forward rapidity with ALICE at the LHC: The ALICE collaboration has studied inclusive J/$\\psi$ and $\\psi$(2S)\nproduction at forward rapidities in pp collisions at $\\sqrt{s} = 7$ TeV with\nthe ALICE Muon Spectrometer. The analysis has been carried out on a data sample\ncorresponding to an integrated luminosity $\\mathcal{L}_{\\rm int}$ = 1.35\npb$^{-1}$. The production cross-sections of J/$\\psi$ and $\\psi$(2S), integrated\nover the transverse momentum (0 $<$ $p_{{\\mathrm T}}$ $<$ 20 GeV/$c$) and\nrapidity (2.5 $<$ $y$ $<$ 4), have been measured. The J/$\\psi$ and $\\psi$(2S)\ndifferential cross-sections, in transverse momentum and rapidity, have also\nbeen measured, significantly extending the $p_{{\\mathrm T}}$ reach of previous\nmeasurements performed in the same $y$-range. The results have been compared\nwith the previously published ALICE results ($\\mathcal{L}_{\\rm int}$ = 15.6\nnb$^{-1}$) and also with the measurement performed by the LHCb collaboration.\nThe $\\psi$(2S)/J/$\\psi$ ratio, integrated over $p_{{\\mathrm T}}$ and $y$, has\nbeen measured. This ratio has also been evaluated as a function of transverse\nmomentum and rapidity and compared with the LHCb measurement. Finally, recent\nresults on cross-sections, $\\psi$(2S)/J/$\\psi$ production ratio, nuclear\nmodification factor ($R_{\\rm pPb}$) and forward-to-backward yield ratio\n($R_{\\rm FB}$) in p-Pb collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV will be\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Acceptance effects in the hyperons global polarization measurement: The possible sources of systematic uncertainties in the hyperons global\npolarization measurement are discussed. The equation with detector acceptance\neffects taken into account is provided. Contribution of the hyperons directed\nflow into the hyperons global polarization measurement is shown. The systematic\nuncertainties of the Lambda hyperons global polarization measurement in Au+Au\ncollisions with the STAR detector at RHIC are calculated.", + "category": "nucl-ex" + }, + { + "text": "Differential studies of inclusive J/$\u03c8$ and $\u03c8$(2S) production at\n forward rapidity in Pb-Pb collisions at $\\mathbf{\\sqrt{{\\textit s}_{_{NN}}}}$\n = 2.76 TeV: The production of J/$\\psi$ and $\\psi(2S)$ was measured with the ALICE\ndetector in Pb-Pb collisions at the LHC. The measurement was performed at\nforward rapidity ($2.5 < y < 4 $) down to zero transverse momentum ($p_{\\rm\nT}$) in the dimuon decay channel. Inclusive J/$\\psi$ yields were extracted in\ndifferent centrality classes and the centrality dependence of the average\n$p_{\\rm T}$ is presented. The J/$\\psi$ suppression, quantified with the nuclear\nmodification factor ($R_{\\rm AA}$), was studied as a function of centrality,\ntransverse momentum and rapidity. Comparisons with similar measurements at\nlower collision energy and theoretical models indicate that the J/$\\psi$\nproduction is the result of an interplay between color screening and\nrecombination mechanisms in a deconfined partonic medium, or at its\nhadronization. Results on the $\\psi(2S)$ suppression are provided via the ratio\nof $\\psi(2S)$ over J/$\\psi$ measured in pp and Pb-Pb collisions.", + "category": "nucl-ex" + }, + { + "text": "Dielectron production in proton-proton collisions at $\\sqrt{s} = 7$ TeV\n with ALICE: The ALICE Collaboration measured dielectron production as a function of the\ninvariant mass ($m_{\\rm ee}$), the pair transverse momentum ($p_{\\rm T,ee}$)\nand the pair distance of closest approach ($\\rm DCA_{ee}$) in pp collisions at\n$\\sqrt{s} = 7$ TeV. Prompt and non-prompt dielectron sources can be separated\nwith the $\\rm DCA_{ee}$, which will give the opportunity in heavy-ion\ncollisions to identify thermal radiation from the medium in the\nintermediate-mass range dominated by contributions from open-charm and beauty\nhadron decays. The charm and beauty total cross sections are extracted from the\ndata by fitting the spectra with two different MC generators, i.e. PYTHIA a\nleading order event generator and POWHEG a next-to-leading order event\ngenerator. Significant model dependences are observed, reflecting the\nsensitivity of this measurement to the heavy-flavour production mechanisms.", + "category": "nucl-ex" + }, + { + "text": "The beta-decay of 22Al: In an experiment performed at the LISE3 facility of GANIL, we studied the\ndecay of 22Al produced by the fragmentation of a 36Ar primary beam. A\nbeta-decay half-life of 91.1 +- 0.5 ms was measured. The beta-delayed one- and\ntwo-proton emission as well as beta-alpha and beta-delayed gamma decays were\nmeasured and allowed us to establish a partial decay scheme for this nucleus.\nNew levels were determined in the daughter nucleus 22Mg. The comparison with\nmodel calculations strongly favours a spin-parity of 4+ for the ground state of\n22Al.", + "category": "nucl-ex" + }, + { + "text": "Coherent photonuclear reactions for isotope transmutation: Coherent photonuclear isotope transmutation (CPIT) produces exclusively\nradioactive isotopes (RIs) by coherent photonuclear reactions via E1 giant\nresonances. Photons to be used are medium energy photons produced by laser\nphotons backscattered off GeV electrons. The cross sections are as large as 0.2\n- 0.6 b, being independent of individual nuclides. A large fraction of photons\nis effectively used for the photonuclear reactions, while the scattered GeV\nelectrons remain in the storage ring to be re-used. CPIT with medium energy\nphotons provides specific/desired RIs with the high rate and the high density\nfor nuclear science, molecular biology and for nuclear medicines.", + "category": "nucl-ex" + }, + { + "text": "A Future Polarized Drell-Yan Experiment at Fermilab: One of the great challenges of QCD is trying to understand the origin of the\nnucleon spin. Several decades of experimental measurements have shown that our\ncurrent understanding is incomplete if only the quark and gluon spin\ncontribution is considered. Over the last few years it has become increasingly\nclear that the contribution from the orbital angular momentum of the quarks and\ngluons has to be included as well. For instance, the sea quark orbital\ncontribution remains largely unexplored. Measurements accessing the sea quark\nSivers distribution will provide a probe of the sea quark orbital contribution.\nThe upcoming E1039 experiment at Fermilab will access this distribution via the\nDrell-Yan process using a 120 GeV unpolarized proton beam directed on a\npolarized proton target. At E1039 kinematics the $u$-$\\bar{u}$ annihilation\nprocess dominates the Drell-Yan cross section ($x_{Target}$ = 0.1 $\\sim$ 0.35).\nIf the $\\bar{u}$ quark carries zero net angular momentum, then the measured\nDrell-Yan single-spin asymmetry should be zero, and vice versa. This experiment\nis a continuation of the currently running SeaQuest experiment.", + "category": "nucl-ex" + }, + { + "text": "Production of ${\\rm K}^{0}_{\\rm{S}}$, $\u039b$ ($\\bar\u039b$),\n $\u039e^{\\pm}$ and $\u03a9^{\\pm}$ in jets and in the underlying event in pp and\n p$-$Pb collisions: The production of strange hadrons (K$^{0}_{\\rm S}$, $\\Lambda$, $\\Xi^{\\pm}$,\nand $\\Omega^{\\pm}$), baryon-to-meson ratios ($\\Lambda/{\\rm K}^0_{\\rm S}$,\n$\\Xi/{\\rm K}^0_{\\rm S }$, and $\\Omega/{\\rm K}^0_{\\rm S}$), and baryon-to-baryon\nratios ($\\Xi/\\Lambda$, $\\Omega/\\Lambda$, and $\\Omega/\\Xi$) associated with jets\nand the underlying event were measured as a function of transverse momentum\n($p_{\\rm T}$) in pp collisions at $\\sqrt{s} = 13$ TeV and p-Pb collisions at\n$\\sqrt{s_{\\rm NN}} = 5.02$ TeV with the ALICE detector at the LHC. The\ninclusive production of the same particle species and the corresponding ratios\nare also reported. The production of multi-strange hadrons, $\\Xi^{\\pm}$ and\n$\\Omega^{\\pm}$, and their associated particle ratios in jets and in the\nunderlying event are measured for the first time. In both pp and p-Pb\ncollisions, the baryon-to-meson and baryon-to-baryon yield ratios measured in\njets differ from the inclusive particle production for low and intermediate\nhadron $p_{\\rm T}$ (0.6$-$6 GeV/$c$). Ratios measured in the underlying event\nare in turn similar to those measured for inclusive particle production. In pp\ncollisions, the particle production in jets is compared with PYTHIA 8\npredictions with three colour-reconnection implementation modes. None of them\nfully reproduces the data in the measured hadron $p_{\\rm T}$ region. The\nmaximum deviation is observed for $\\Xi^{\\pm}$ and $\\Omega^{\\pm}$, which reaches\na factor of about six. In p-Pb collisions, there is no significant\nevent-multiplicity dependence for particle production in jets, in contrast to\nwhat is observed in the underlying event. The presented measurements provide\nnovel constraints on hadronisation and its Monte Carlo description. In\nparticular, they demonstrate that the fragmentation of jets alone is\ninsufficient to describe the strange and multi-strange particle production in\nhadronic collisions at LHC energies.", + "category": "nucl-ex" + }, + { + "text": "Radioisotopes production using lasers: from basic science to\n applications: Laser technologies improved after the understanding of the Chirped Pulse\nAmplification (CPA) which allows energetic laser beams to be compressed to tens\nof femtosecond (fs) pulse durations and focused to few $\\mu$m. Protons of tens\nof MeV can be accelerated using for instance the Target Normal Sheath\nAcceleration (TNSA) method and focused on secondary targets. In such\nconditions, nuclear reactions can occur and radioisotopes relevant for medical\npurposes be produced. High repetition lasers can be used to produce enough\nisotopes for medical applications. This route is competitive to conventional\nmethods mostly based on accelerators. In this paper we study the production of\n$^{67}$Cu, $^{63}$Zn, $^{18}$F and $^{11}$C currently used in positron emission\ntomography (PET) and other applications. At the same time, we study the\nreaction $^{10}$B(p,$\\alpha$)$^{7}$Be and $^{70}$Zn(p,4n)$^{67}$Ga to put\nfurther constraints to the proton distributions at different angles and to the\nreaction $^{11}$B(p,$\\alpha$)$^{8}$Be relevant for energy production. The\nexperiment was performed at the 1 petawatt (PW) laser facility at Vega III\nlocated in Salamanca-Spain. Angular distributions of radioisotopes in the\nforward (with respect to the laser direction) and backward directions were\nmeasured using a High Purity Germanium Detector (HPGE). Our results are\nreasonably reproduced by the numerical estimates following the approach of\nKimura et al. (NIMA637(2011)167)", + "category": "nucl-ex" + }, + { + "text": "Measurement of azimuthal anisotropy of muons from charm and bottom\n hadrons in Pb+Pb collisions at $\\sqrt{s_\\mathrm{NN}} = 5.02$ TeV with the\n ATLAS detector: Azimuthal anisotropies of muons from charm and bottom hadron decays are\nmeasured in Pb+Pb collisions at $\\sqrt{s_\\mathrm{NN}}= 5.02$ TeV. The data were\ncollected with the ATLAS detector at the Large Hadron Collider in 2015 and 2018\nwith integrated luminosities of $0.5~\\mathrm{nb}^{-1}$ and\n$1.4~\\mathrm{nb^{-1}}$, respectively. The kinematic selection for heavy-flavor\nmuons requires transverse momentum $4 < p_\\mathrm{T} < 30$ GeV and\npseudorapidity $|\\eta|<2.0$. The dominant sources of muons in this\n$p_\\mathrm{T}$ range are semi-leptonic decays of charm and bottom hadrons.\nThese heavy-flavor muons are separated from light-hadron decay muons and\npunch-through hadrons using the momentum imbalance between the measurements in\nthe tracking detector and in the muon spectrometers. Azimuthal anisotropies,\nquantified by flow coefficients, are measured via the event-plane method for\ninclusive heavy-flavor muons as a function of the muon $p_\\mathrm{T}$ and in\nintervals of Pb+Pb collision centrality. Heavy-flavor muons are separated into\ncontributions from charm and bottom hadron decays using the muon transverse\nimpact parameter with respect to the event primary vertex. Non-zero elliptic\n($v_{2}$) and triangular ($v_{3}$) flow coefficients are extracted for charm\nand bottom muons, with the charm muon coefficients larger than those for bottom\nmuons for all Pb+Pb collision centralities. The results indicate substantial\nmodification to the charm and bottom quark angular distributions through\ninteractions in the quark-gluon plasma produced in these Pb+Pb collisions, with\nsmaller modifications for the bottom quarks as expected theoretically due to\ntheir larger mass.", + "category": "nucl-ex" + }, + { + "text": "Octupole strength in the neutron-rich calcium isotopes: Low-lying excited states of the neutron-rich calcium isotopes $^{48-52}$Ca\nhave been studied via $\\gamma$-ray spectroscopy following inverse-kinematics\nproton scattering on a liquid hydrogen target using the GRETINA $\\gamma$-ray\ntracking array. The energies and strengths of the octupole states in these\nisotopes are remarkably constant, indicating that these states are dominated by\nproton excitations.", + "category": "nucl-ex" + }, + { + "text": "Indications for a critical point in the phase diagram for hot and dense\n nuclear matter: Two-pion interferometry measurements are studied for a broad range of\ncollision centralities in Au+Au (Root_s = 7.7 - 200 GeV) and Pb+Pb (Root_s =\n2.76 TeV) collisions. They indicate non-monotonic excitation functions for the\nGaussian emission source radii difference [(R_out)^2 - (R_side)^2], suggestive\nof reaction trajectories which spend a fair amount of time near a \"soft point\"\nin the equation of state (EOS) that coincides with the critical end point\n(CEP). A Finite-Size Scaling (FSS) analysis of these excitation functions,\nprovides further validation tests for the CEP. It also indicates a second order\nphase transition at the CEP, and the values T^{cep} ~ 165 MeV and mu_B^{cep} ~\n95 MeV for its location in the (T, mu_B)-plane of the phase diagram. The static\ncritical exponents (nu ~ 0.66 and gamma ~ 1.2) extracted via the same FSS\nanalysis, place this CEP in the 3D Ising model universality class. A Dynamic\nFinite-Size Scaling analysis of the excitation functions, gives the estimate z\n~ 0.87 for the dynamic critical exponent, suggesting that the associated\ncritical expansion dynamics is dominated by the hydrodynamic sound mode.", + "category": "nucl-ex" + }, + { + "text": "Study of the ground and excited states of Lambda and Sigma hyperon\n production at COSY: COSY with a maximum beam momentum of ~3.65 GeV/c allows the production of\nground state (Lambda and Sigma) and excited hyperons (Lambda(1405), Sigma(1385)\nand Lambda(1520)) in elementary NN interactions. The existing data base in this\nfield is rather poor. A systematic study of the hyperon production at COSY will\nresult in an improvement of our understanding concerning topics like\nhyperon-nucleon interaction, kaon-nucleon interaction, nucleon resonances,\nstrangeness production mechanism and structure of the Lambda(1405). Precise\ndata on Lambda and Sigma production have been produced at the COSY-11 and TOF\ninstallation. With the WASA detector at COSY these studies can be continued and\nextended to channels including photons in the final state.", + "category": "nucl-ex" + }, + { + "text": "High-precision mass measurement of $^{56}$Cu and the redirection of the\n rp-process flow: We report the mass measurement of $^{56}$Cu, using the LEBIT 9.4T Penning\ntrap mass spectrometer at the National Superconducting Cyclotron Laboratory at\nMichigan State University. The mass of $^{56}$Cu is critical for constraining\nthe reaction rates of the\n$^{55}$Ni(p,$\\gamma$)$^{56}$Cu(p,$\\gamma$)$^{57}$Zn($\\beta^+$)$^{57}$Cu bypass\naround the $^{56}$Ni waiting point. Previous recommended mass excess values\nhave disagreed by several hundred keV. Our new value, ME=$-38 626.7(6.4)$ keV,\nis a factor of 30 more precise than the suggested value from the 2012 atomic\nmass evaluation [Chin. Phys. C {\\bf{36}}, 1603 (2012)], and more than a factor\nof 12 more precise than values calculated using local mass extrapolations,\nwhile agreeing with the newest 2016 atomic mass evaluation value [Chin. Phys. C\n{\\bf{41}}, 030003 (2017)]. The new experimental average was used to calculate\nthe astrophysical $^{55}$Ni(p,$\\gamma$) and $^{57}$Zn($\\gamma$,p) reaction\nrates and perform reaction network calculations of the rp-process. These show\nthat the rp-process flow redirects around the $^{56}$Ni waiting point through\nthe $^{55}$Ni(p,$\\gamma$) route, allowing it to proceed to higher masses more\nquickly and resulting in a reduction in ashes around this waiting point and an\nenhancement to higher-mass ashes.", + "category": "nucl-ex" + }, + { + "text": "Secondary nuclear fragment beams for investigations of relativistic\n fragmentation of light radioactive nuclei using nuclear photoemulsion at\n Nuclotron: Slowly extracted relativistic beams of light nuclei and a beam transportation\nline net system constitute a good base for secondary nuclear beams forming at\nthe LHE accelerator facility. A recent years activity in the field at the\nLaboratory is connected with a project on study light nuclei structure by means\nthe emulsion technique [1,2]. The paper shortly summarizes results of the work.", + "category": "nucl-ex" + }, + { + "text": "The i11/2 f5/2 and i11/2 p3/2 neutron particle-hole multiplets in 208Pb: Inelastic proton scattering via isobaric analog resonances allows to derive\nrather complete information about neutron particle-hole states. We applied this\nmethod to the doubly-magic nucleus 208Pb by measuring angular distributions of\n208Pb(p, p') on top of the isobaric analog resonances in 209Bi with the Q3D\nmagnetic spectrograph at M\\\"unchen. We identify the six states of the i11/2\nf5/2 multiplet and the four states of the i11/2 p3/2 multiplet in the energy\nrange 4.6 MeV < Ex < 5.3 MeV. Firm spin assignments for the ten states are\ngiven, some of them new. Additional measurements of the reaction 207Pb(d, p)\nconfirm the fragmented i11/2 p1/2 multiplet.", + "category": "nucl-ex" + }, + { + "text": "Experimental neutron capture data of $^{58}$Ni from the CERN n_TOF\n facility: The $^{58}$Ni $(n,\\gamma)$ cross section has been measured at the neutron\ntime of flight facility n_TOF at CERN, in the energy range from 27 meV up to\n400 keV. In total, 51 resonances have been analyzed up to 122 keV. Maxwellian\naveraged cross sections (MACS) have been calculated for stellar temperatures of\nkT$=$5-100 keV with uncertainties of less than 6%, showing fair agreement with\nrecent experimental and evaluated data up to kT = 50 keV. The MACS extracted in\nthe present work at 30 keV is 34.2$\\pm$0.6$_\\mathrm{stat}\\pm$1.8$_\\mathrm{sys}$\nmb, in agreement with latest results and evaluations, but 12% lower relative to\nthe recent KADoNIS compilation of astrophysical cross sections. When included\nin models of the s-process nucleosynthesis in massive stars, this change\nresults in a 60% increase of the abundance of $^{58}$Ni, with a negligible\npropagation on heavier isotopes. The reason is that, using both the old or the\nnew MACS, 58Ni is efficiently depleted by neutron captures.", + "category": "nucl-ex" + }, + { + "text": "A New Measurement of the 6Li(n,\u03b1)t Cross Section at MeV Energies\n Using a Fission Chamber and 6Li Scintillators: A new measurement is presented of the $^6$Li(n,$\\alpha$)t cross section from\n245 keV to 10 MeV using a $^{252}$Cf fission chamber with $^6$LiI(Eu) and\nCs$_2$LiYCl$_6$:Ce (CLYC) scintillators which act as both target and detector.\nNeutron energies are determined from the time of flight (TOF) method using the\nsignals from spontaneous fission and reaction product recoil. Simulations of\nneutron downscatter in the crystals and fission chamber bring\n$^6$Li(n,$\\alpha$)t cross section values measured with the $^6$LiI(Eu) into\nagreement with previous experiments and evaluations, except for two resonances\nat 4.2 and 6.5 MeV introduced by ENDF/B-VII.1. Suspected neutron transport\nmodeling issues cause the cross section values obtained with CLYC to be\ndiscrepant above 2 MeV.", + "category": "nucl-ex" + }, + { + "text": "Freeze-out radii extracted from three-pion cumulants in pp, p-Pb and\n Pb-Pb collisions at the LHC: In high-energy collisions, the spatio-temporal size of the particle\nproduction region can be measured using the Bose-Einstein correlations of\nidentical bosons at low relative momentum. The source radii are typically\nextracted using two-pion correlations, and characterize the system at the last\nstage of interaction, called kinetic freeze-out. In low-multiplicity\ncollisions, unlike in high-multiplicity collisions, two-pion correlations are\nsubstantially altered by background correlations, e.g. mini-jets. Such\ncorrelations can be suppressed using three-pion cumulant correlations. We\npresent the first measurements of the size of the system at freeze-out\nextracted from three-pion cumulant correlations in pp, p-Pb and Pb-Pb\ncollisions at the LHC with ALICE. At similar multiplicity, the invariant radii\nextracted in p-Pb collisions are found to be 5-15% larger than those in pp,\nwhile those in Pb-Pb are 35-55% larger than those in p-Pb. Our measurements\ndisfavor models which incorporate substantially stronger collective expansion\nin p-Pb as compared to pp collisions at similar multiplicity.", + "category": "nucl-ex" + }, + { + "text": "Shape changes in the mirror nuclei $^{70}$Kr and $^{70}$Se: We studied the proton-rich $T_z=-1$ nucleus $^{70}$Kr through inelastic\nscattering at intermediate energies in order to extract the reduced transition\nprobability, $B(E2;\\;0^+ \\rightarrow 2^+)$. Comparison with the other members\nof the $A=70$ isospin triplet, $^{70}$Br and $^{70}$Se, studied in the same\nexperiment, shows a $3\\sigma$ deviation from the expected linearity of the\nelectromagnetic matrix elements as a function of $T_z$.\n At present, no established nuclear structure theory can describe this\nobserved deviation quantitatively. This is the first violation of isospin\nsymmetry at this level observed in the transition matrix elements. A heuristic\napproach may explain the anomaly by a shape change between the mirror nuclei\n$^{70}$Kr and $^{70}$Se contrary to the model predictions.", + "category": "nucl-ex" + }, + { + "text": "Correlations of electrons from heavy flavor decay in p+p, d+Au and Au+Au\n collisions: In relativistic heavy ion collisions heavy flavor probes are crucial to\nunderstand the interactions between partons and the produced hot nuclear\nmatter. Measurements in p+p collisions provide information about how the heavy\nquarks are produced and fragment and in d+Au collisions are sensitive to\npossible effects from cold nuclear matter. Azimuthal correlation measurements\ninvolving heavy flavor probes are complementary to single particle spectra\nmeasurements and provide additional information about production and\ninteractions of heavy quarks. Measurements of electrons with heavy flavor decay\nwith other hadrons from the event can provide information about how the heavy\nquark interacts with the produced matter and can be compared to similar\nmeasurements from light hadron correlations. Correlations between electrons\nfrom heavy flavor decay with muons, also from heavy flavor decay, can provide\nfurther information about heavy flavor production and cold nuclear matter\neffects in d+Au collisions with a very clean signal. We present PHENIX results\nfor electron-hadron correlations in p+p and Au+Au collisions and electron-muon\ncorrelations in p+p and d+Au collisions and discuss the implications of these\nmeasurements.", + "category": "nucl-ex" + }, + { + "text": "Proton induced reactions on naturalU at 62.9 MeV: Double differential cross sections (DDCS) for light charged particles\n(proton, deuteron, triton, 3He, alpha) and neutrons produced by a proton beam\nimpinging on a 238U target at 62.9 MeV were measured at the CYCLONE facility in\nLouvain-la-Neuve (Belgium). These measurements have been performed using two\nindependent experimental set-ups ensuring neutron (DeMoN counters) and light\ncharged particles (Si-Si-CsI telescopes) detection. The charged particle data\nwere measured at 11 different angular positions from 25 degrees to 140 degrees\nallowing the determination of angle differential, energy differential and total\nproduction cross sections.", + "category": "nucl-ex" + }, + { + "text": "Cross section for $b\\bar{b}$ production via dielectrons in d$+$Au\n collisions at $\\sqrt{s_{_{NN}}}=200$ GeV: We report a measurement of $e^+e^-$ pairs from semileptonic heavy-flavor\ndecays in $d$$+$Au collisions at $\\sqrt{s_{_{NN}}}=200$ GeV. Exploring the mass\nand transverse-momentum dependence of the yield, the bottom decay contribution\ncan be isolated from charm, and quantified by comparison to {\\sc pythia} and\n{\\sc mc@nlo} simulations. The resulting $b\\bar{b}$-production cross section is\n$\\sigma^{d{\\rm Au}}_{b\\bar{b}}=1.37{\\pm}0.28({\\rm stat}){\\pm}0.46({\\rm\nsyst})$~mb, which is equivalent to a nucleon-nucleon cross section of\n$\\sigma^{NN}_{bb}=3.4\\pm0.8({\\rm stat}){\\pm}1.1({\\rm syst})\\ \\mu$b.", + "category": "nucl-ex" + }, + { + "text": "Inclusive pion and eta production in p+Nb collisions at 3.5 GeV beam\n energy: Data on inclusive pion and eta production measured with the dielectron\nspectrometer HADES in the reaction p+93Nb at a kinetic beam energy of 3.5 GeV\nare presented. Our results, obtained with the photon conversion method,\nsupplement the rather sparse information on neutral meson production in\nproton-nucleus reactions existing for this bombarding energy regime. The\nreconstructed e+e-e+e- transverse-momentum and rapidity distributions are\nconfronted with transport model calculations, which account fairly well for\nboth pi0 and eta production.", + "category": "nucl-ex" + }, + { + "text": "Production and Flow of Identified Hadrons at RHIC: We review the production and flow of identified hadrons at RHIC with a main\nemphasis on the intermediate transverse momentum region ($2< p_{T} <5$\nGeV/$c$). The goal is to unravel the dynamics of baryon production and resolve\nthe anomalously large baryon yields and elliptic flow observed in the\nexperiments.", + "category": "nucl-ex" + }, + { + "text": "A Facility for Low-energy Antiproton and Ion Research: The future accelerator facility for beams of ions and antiprotons at\nDarmstadt will provide antiproton beams of intensities that are two orders of\nmagnitude higher than currently available. Within the foreseen scheme,\nantiprotons can be decelerated to 30 MeV. The low-energy antiproton community\nhas recently formed a users group to make use of this opportunity to create a\nnext-generation low-energy antiproton facility called FLAIR, which will be able\nto provide cooled antiproton beams well below 100 keV kinetic energy. This talk\ngives an overview of the layout and physics program of the proposed facility.", + "category": "nucl-ex" + }, + { + "text": "A solenoidal electron spectrometer for a precision measurement of the\n neutron $\u03b2$-asymmetry with ultracold neutrons: We describe an electron spectrometer designed for a precision measurement of\nthe neutron $\\beta$-asymmetry with spin-polarized ultracold neutrons. The\nspectrometer consists of a 1.0-Tesla solenoidal field with two identical\nmultiwire proportional chamber and plastic scintillator electron detector\npackages situated within 0.6-Tesla field-expansion regions. Select results from\nperformance studies of the spectrometer with calibration sources are reported.", + "category": "nucl-ex" + }, + { + "text": "Electroweak probes with ATLAS: Measuring electroweak bosons in relativistic heavy ion collisions at high\nenergy provide an opportunity to understand temporal evolution of the\nquark-gluon plasma created in such collisions by constraining the initial state\nof the interaction. Due to lack of color charges the bosons and or particles\nproduced in their leptonic decays are unaffected by the quark-gluon plasma and\ntherefore preserve the information about the very early stage of the collision\nwhen they were born. This singles electroweak bosons as a unique and very\ninteresting class of observables in heavy ion collisions. The ATLAS experiment\nat LHC measures production of electroweak bosons in pp, p+Pb, and Pb + Pb\ncollisions systems. A review of the existing results is given in this\nproceeding that includes studies made with isolated photons to constraint\nkinematic properties and flavour composition of associated jets, measurements\nof W and Z bosons used to estimate nuclear modification of parton distribution\nfunction and the production rates of the bosons used to verify geometric models\nimplied to estimate event centrality. A novel analysis on measuring\ntwo-particle correlations in pp collisions where the Z boson is registered is\nalso discussed in the proceeding. This is the first attempt to break into the\ninitial geometry of the pp collisions by constraining the impact parameter with\na hard scattering process. It shows that the strength of the two particle\ncorrelations in such collision is 1.08+/-0.06 above the inclusive. To make the\nmeasurement ATLAS solves the technical problem of measuring the underlying\nevent in high pileup condition.", + "category": "nucl-ex" + }, + { + "text": "Polarization in Hyperon Photo- and Electro- Production: Multiple polarization observables must be measured to access the amplitude\nstructure of pseudoscalar meson photoproduction off the proton. The\nhyperon-producing reactions are especially attractive to study, since the weak\ndecays allow straightforward measurement of the induced and recoil polarization\nobservables. In this paper we emphasize $\\gamma + p \\to K^+ + \\Lambda$,\ndiscussing recent measurements of $C_x$, $C_z$, and $P$ for this reaction. An\nempirical constraint on the helicity amplitudes is obtained. A simplified model\ninvolving spin-flip and spin non-flip amplitudes is presented. Finally, a\nsemi-classical model of how the polarization may arise is presented.", + "category": "nucl-ex" + }, + { + "text": "Non-equilibrium emission of complex fragments from p+Au collisions at\n 2.5 GeV proton beam energy: Energy and angular dependence of double differential cross sections\nd$^2\\sigma$/d$\\Omega$dE was measured for reactions induced by 2.5 GeV protons\non Au target with isotopic identification of light products (H, He, Li, Be, and\nB) and with elemental identification of heavier intermediate mass fragments (C,\nN, O, F, Ne, Na, Mg, and Al). It was found that two different reaction\nmechanisms give comparable contributions to the cross sections. The\nintranuclear cascade of nucleon-nucleon collisions followed by evaporation from\nan equilibrated residuum describes low energy part of the energy distributions\nwhereas another reaction mechanism is responsible for high energy part of the\nspectra of composite particles. Phenomenological model description of the\ndifferential cross sections by isotropic emission from two moving sources led\nto a very good description of all measured data. Values of the extracted\nparameters of the emitting sources are compatible with the hypothesis claiming\nthat the high energy particles emerge from pre-equilibrium processes consisting\nin a breakup of the target into three groups of nucleons; small, fast and hot\nfireball of $\\sim$ 8 nucleons, and two larger, excited prefragments, which\nemits the light charged particles and intermediate mass fragments. The smaller\nof them contains $\\sim$ 20 nucleons and moves with velocity larger than the CM\nvelocity of the proton projectile and the target. The heavier prefragment\nbehaves similarly as the heavy residuum of the intranuclear cascade of\nnucleon-nucleon collisions. %The mass and charge dependence of the total\nproduction cross %sections was extracted from the above analysis for all\nobserved %reaction products. This dependence follows the power low behavior\n%(A$^{-\\tau}$ or Z$^{-\\tau}$).", + "category": "nucl-ex" + }, + { + "text": "Study of jet quenching with Z+jet correlations in PbPb and pp collisions\n at sqrt(s[NN]) = 5.02 TeV: The production of jets in association with Z bosons, reconstructed via the\nmu+mu- and e+e- decay channels, is studied in pp and, for the first time, in\nPbPb collisions. Both data samples were collected by the CMS experiment at the\nLHC, at a nucleon-nucleon center-of-mass energy of 5.02 TeV. The PbPb\ncollisions were analyzed in the 0-30% centrality range. The back-to-back\nazimuthal alignment was studied in both pp and PbPb collisions for Z bosons\nwith transverse momentum p[tz] > 60 GeV/c and a recoiling jet with p[tj] > 30\nGeV/c. The pt imbalance, x[jz] = p[tj] / p[tz], as well as the average number\nof jet partners per Z, R[jz], were studied in intervals of p[tz], in both pp\nand PbPb collisions. The R[jz] is found to be smaller in PbPb than in pp\ncollisions, which suggests that in PbPb collisions a larger fraction of\npartons, associated with the Z bosons, lose energy and fall below the 30 GeV/c\np[tj] threshold.", + "category": "nucl-ex" + }, + { + "text": "Recent Progress in Double Beta Decay: At least one neutrino has a mass of about 50 meV or larger. However, the\nabsolute mass scale for the neutrino remains unknown. Studies of double beta\ndecay offer hope for determining the absolute mass scale. Furthermore, the\ncritical question: Is the neutrino its own antiparticle? is unanswered. In\nparticular, zero-neutrino double beta decay can address the issues of lepton\nnumber conservation, the particle-antiparticle nature of the neutrino, and its\nmass. A summary of the recent progress in double beta decay, and the related\ntechnologies will be discussed in the context of the future double beta decay\nprogram.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the $^{14}$N(n,p)$^{14}$C cross section at the CERN n_TOF\n facility from sub-thermal energy to 800 keV: Background: The $^{14}$N(n,p)$^{14}$C reaction is of interest in neutron\ncapture therapy, where nitrogen-related dose is the main component due to\nlow-energy neutrons, and in astrophysics, where 14N acts as a neutron poison in\nthe s-process. Several discrepancies remain between the existing data obtained\nin partial energy ranges: thermal energy, keV region and resonance region.\nPurpose: Measuring the 14N(n,p)14C cross section from thermal to the resonance\nregion in a single measurement for the first time, including characterization\nof the first resonances, and providing calculations of Maxwellian averaged\ncross sections (MACS). Method: Time-of-flight technique. Experimental Area 2\n(EAR-2) of the neutron time-of-flight (n_TOF) facility at CERN.\n$^{10}$B(n,${\\alpha}$)$^7$Li and $^{235}$U(n,f) reactions as references. Two\ndetection systems running simultaneously, one on-beam and another off-beam.\nDescription of the resonances with the R-matrix code sammy. Results: The cross\nsection has been measured from sub-thermal energy to 800 keV resolving the two\nfirst resonances (at 492.7 and 644 keV). A thermal cross-section\n(1.809$\\pm$0.045 b) lower than the two most recent measurements by slightly\nmore than one standard deviation, but in line with the ENDF/B-VIII.0 and\nJEFF-3.3 evaluations has been obtained. A 1/v energy dependence of the cross\nsection has been confirmed up to tens of keV neutron energy. The low energy\ntail of the first resonance at 492.7 keV is lower than suggested by evaluated\nvalues, while the overall resonance strength agrees with evaluations.\nConclusions: Our measurement has allowed to determine the $^{14}$N(n,p)\ncross-section over a wide energy range for the first time. We have obtained\ncross-sections with high accuracy (2.5 %) from sub-thermal energy to 800 keV\nand used these data to calculate the MACS for kT = 5 to kT = 100 keV.", + "category": "nucl-ex" + }, + { + "text": "Improved search for two-neutrino double electron capture on $^{124}$Xe\n and $^{126}$Xe using particle identification in XMASS-I: We conducted an improved search for the simultaneous capture of two $K$-shell\nelectrons on the $^{124}$Xe and $^{126}$Xe nuclei with emission of two\nneutrinos using 800.0 days of data from the XMASS-I detector. A novel method to\ndiscriminate $\\gamma$-ray/$X$-ray or double electron capture signals from\n$\\beta$-ray background using scintillation time profiles was developed for this\nsearch. No significant signal was found when fitting the observed energy\nspectra with the expected signal and background. Therefore, we set the most\nstringent lower limits on the half-lives at $2.1 \\times 10^{22}$ and $1.9\n\\times 10^{22}$ years for $^{124}$Xe and $^{126}$Xe, respectively, with 90%\nconfidence level. These limits improve upon previously reported values by a\nfactor of 4.5.", + "category": "nucl-ex" + }, + { + "text": "Comment on \"Search for new particles decaying into electron pairs of\n mass below 100 MeV/c^2\": A re-analysis of data from electron-pair production following 160 A GeV 207Pb\nbombardment of nuclear emulsions indicates the production and decay of neutral\nparticles of significantly lower invariant mass and shorter lifetimes than\npreviously claimed (J. Phys. G: Nucl. Part. Phys. 34 (2007) 129-138).", + "category": "nucl-ex" + }, + { + "text": "Breakup Conditions of Projectile Spectators from Dynamical Observables: Momenta and masses of heavy projectile fragments (Z >= 8), produced in\ncollisions of 197Au with C, Al, Cu and Pb targets at E/A = 600 MeV, were\ndetermined with the ALADIN magnetic spectrometer at SIS. An analysis of\nkinematic correlations between the two and three heaviest projectile fragments\nin their rest frame was performed. The sensitivity of these correlations to the\nconditions at breakup was verified within the schematic SOS-model. The data\nwere compared to calculations with statistical multifragmentation models and to\nclassical three-body calculations. Classical trajectory calculations reproduce\nthe dynamical observables. The deduced breakup parameters, however, differ\nconsiderably from those assumed in the statistical multifragmentation models\nwhich describe the charge correlations. If, on the other hand, the analysis of\nkinematic and charge correlations is performed for events with two and three\nheavy fragments produced by statistical multifragmentation codes, a good\nagreement with the data is found with the exception that the fluctuation widths\nof the intrinsic fragment energies are significantly underestimated. A new\nversion of the multifragmentation code MCFRAG was therefore used to investigate\nthe potential role of angular momentum at the breakup stage. If a mean angular\nmomentum of 0.75$\\hbar$/nucleon is added to the system, the energy fluctuations\ncan be reproduced, but at the same time the charge partitions are modified and\ndeviate from the data.\n PACS numbers: 25.70.Mn, 25.70.Pq, 25.75.Ld, 25.75.-q", + "category": "nucl-ex" + }, + { + "text": "Neutral meson production in d+Au and p+p collisions at sqrt(s_NN) = 200\n GeV in STAR: The high centre-of-mass energy of 200 GeV available at the Relativistic Heavy\nIon Collider (RHIC) at Brookhaven opens up the hard scattering regime in\nheavy-ion collisions. Particles at large transverse momentum originate from the\nearly stage of the interaction and, therefore, probe the medium produced in\nthese collisions. To quantitatively understand the medium induced modification\nof hadron production, precise measurements of identified hadrons in p+p and\nd+Au systems are required. This thesis presents the high transverse momentum\nmeasurements of neutral pions and eta mesons through their di-photon decay\nchannel, performed with STAR Barrel Electromagnetic Calorimeter. The medium\ninduced spectrum modification in d+Au collisions is also measured in comparison\nto the most peripheral d+Au and to the p+p collisions. The results are\nconsistent with the previous STAR charged hadron measurements and with the\ntheory (QCD) calculations, as well as with measurements from PHENIX, another\nRHIC experiment.", + "category": "nucl-ex" + }, + { + "text": "Quark participants and global observables: We show that the centrality dependence of charged particle and photon\npseudorapidity density at midrapidity along with the transverse energy\npseudorapidity density at SPS and RHIC energies scales with the number of\nparticipating constituent quarks. The number of charged particles and\ntransverse energy per participant constituent quark is found to increase with\nincrease in beam energy.", + "category": "nucl-ex" + }, + { + "text": "Sideward Flow in Au + Au Collisions Between 2A GeV and 8A GeV: Using the large acceptance Time Projection Chamber of experiment E895 at\nBrookhaven, measurements of collective sideward flow in Au + Au collisions at\nbeam energies of 2, 4, 6 and 8A GeV are presented in the form of in-plane\ntransverse momentum and the first Fourier coefficient of azimuthal\nanisotropy v_1. These measurements indicate a smooth variation of sideward flow\nas a function of beam energy. The data are compared with four nuclear transport\nmodels which have an orientation towards this energy range. All four exhibit\nsome qualitative trends similar to those found in the data, although none shows\na consistent pattern of agreement within experimental uncertainties.", + "category": "nucl-ex" + }, + { + "text": "Single-nucleon experiments: We discuss the Jefferson Lab low momentum transfer data on moments of the\nnucleon spin structure functions $g_1$ and $g_2$ and on single charged pion\nelectroproduction off polarized proton and polarized neutron. A wealth of data\nis now available, while more is being analyzed or expected to be taken in the\nupcoming years. Given the low momentum transfer selected by the experiments,\nthese data can be compared to calculations from Chiral Perturbation theory, the\neffective theory of strong force that should describe it at low momentum\ntransfer. The data on various moments and the respective calculations do not\nconsistently agree. In particular, experimental data for higher moments\ndisagree with the calculations.The absence of contribution from the $\\Delta$\nresonance in the various observables was expected to facilitate the\ncalculations and hence make the theory predictions either more robust or valid\nover a larger $Q^2$ range. Such expectation is verified only for the Bjorken\nsum, but not for other observables in which the $\\Delta$ is suppressed.\nPreliminary results on pion electroproduction off polarized nucleons are also\npresented and compared to phenomenological models for which contributions from\ndifferent resonances are varied. Chiral Perturbation calculations of these\nobservables, while not yet available, would be valuable and, together with\nthese data, would provide an extensive test of the effective theory.", + "category": "nucl-ex" + }, + { + "text": "First measurement of the $|t|$-dependence of incoherent J/$\u03c8$\n photonuclear production: The first measurement of the cross section for incoherent photonuclear\nproduction of J/$\\psi$ vector meson as a function of the Mandelstam $|t|$\nvariable is presented. The measurement was carried out with the ALICE detector\nat midrapidity, $|y|<0.8$, using ultra-peripheral collisions of Pb nuclei at a\ncentre-of-mass energy per nucleon pair $\\sqrt{s_{\\mathrm{NN}}} = 5.02$ TeV.\nThis rapidity interval corresponds to a Bjorken-$x$ range $(0.3$$-$$1.4)\\times\n10^{-3}$. Cross sections are reported in five $|t|$ intervals in the range\n$0.04<|t|<1$~GeV$^2$ and compared to the predictions of different models.\nModels that ignore quantum fluctuations of the gluon density in the colliding\nhadron predict a $|t|$-dependence of the cross section much steeper than in\ndata. The inclusion of such fluctuations in the same models provides a better\ndescription of the data.", + "category": "nucl-ex" + }, + { + "text": "Is $\\hat{q}$ a physical quantity or just a parameter? and other\n unanswered questions in High-$p_T$ Physics: The many different theoretical studies of energy loss of a quark or gluon\ntraversing a medium have one thing in common: the transport coefficient of a\ngluon in the medium, $\\hat{q}$, which is defined as the mean 4-momentum\ntransfer$^2$, $\\left$, by a gluon to the medium per gluon mean free\npath, $\\lambda_{\\rm mfp}$. In the original BDMPSZ formalism, the energy loss of\nan outgoing parton, $-dE/dx$, per unit length ($x$) of a medium with total\nlength $L$, due to coherent gluon bremsstrahlung, is proportional to the\n$\\left< q^2\\right>$ and takes the form: ${-dE/dx }\\simeq \\alpha_s\n\\left<{q^2(L)}\\right>=\\alpha_s\\, \\mu^2\\, L/\\lambda_{\\rm mfp} =\\alpha_s\\,\n\\hat{q}\\, L\\ $ , where $\\mu$, is the mean momentum transfer per collision.\nThus, the total energy loss in the medium goes like $L^2$. Additionally, the\naccumulated momentum$^2$, $\\left<{k_{\\perp}^2}\\right>$, transverse to a gluon\ntraversing a length $L$ in the medium is well approximated by\n$\\left<{k_{\\perp}^2}\\right>\\approx\\left<{q^2(L)}\\right>=\\hat{q}\\, L$.\n A simple estimate shows that the\n$\\left<{k_{\\perp}^2}\\right>\\approx\\hat{q}\\,L$ should be observable at RHIC at\n$\\sqrt{s_{NN}}=200$ GeV via the broadening of di-hadron azimuthal correlations\nresulting in an azimuthal width $\\sim\\sqrt{2}$ larger in Au$+$Au than in $p+p$\ncollisions . Measurements relevant to this issue will be discussed as well as\nrecent STAR jet results presented at QM2014. Other topics to be discussed\ninclude the danger of using forward energy to define centrality in $p(d)+$A\ncollisions for high $p_T$ measurements, the danger of not using comparison\n$p+p$ data at the same $\\sqrt{s}$ in the same detector for $R_{AA}$ or lately\nfor $R_{pA}$ measurements.", + "category": "nucl-ex" + }, + { + "text": "Photoneutron Reactions $^{181}\\rm{Ta}(\u03b3,\\textit{x}n; \\textit{x} = 1\n \u00f78)^{181-\\textit{x}}\\rm{Ta}$ AT $E_{\\rm{\u03b3max}}$ = 80 $\u00f7$ 95 MeV: The bremsstrahlung flux-averaged cross-sections $\\langle{\\sigma(E_{\\rm{\\gamma\nmax}})}\\rangle$ for the $^{181}\\rm{Ta}(\\gamma,\\textit{x}n; \\textit{x} = 1 \\div\n8)^{181-\\textit{x}}\\rm{Ta}$ photoneutron reactions have been measured at\nend-point bremsstrahlung energies ranging from 80 MeV to 95 MeV. The\nmeasurements were performed with the beam from the NSC KIPT electron linear\naccelerator LUE-40 using the residual $\\gamma$-activity method. The theoretical\n$\\langle{\\sigma(E_{\\rm{\\gamma max}})}\\rangle$ values were computed using the\ncross-sections $\\sigma(E)$ from TALYS1.9 code. A comparison between the\nmeasured cross-sections $\\langle{\\sigma(E_{\\rm{\\gamma max}})}\\rangle$ and the\ntheoretical values has demostrated their good agreement for the reactions with\nescape of up to 6 neutrons, and substantial differences for the\n$(\\gamma,7\\rm{n})$ and $(\\gamma,8\\rm{n})$ reactions. Isomeric ratios of the\naverage cross-sections $d(E_{\\rm{\\gamma max}})$ have been found for the\n$^{181}\\rm{Ta}(\\gamma,3n)^{178g,m}\\rm{Ta}$ reaction products. The results have\nbeen compared with the literature data and the computations based on TALYS1.9\ncode.", + "category": "nucl-ex" + }, + { + "text": "Determination of luminosity for in-ring reactions: A new approach for\n the low-energy domain: Luminosity is a measure of the colliding frequency between beam and target\nand it is a crucial parameter for the measurement of absolute values, such as\nreaction cross sections. In this paper, we make use of experimental data from\nthe ESR storage ring to demonstrate that the luminosity can be precisely\ndetermined by modelling the measured Rutherford scattering distribution. The\nobtained results are in good agreement with an independent measurement based on\nthe x-ray normalization method. Our new method provides an alternative way to\nprecisely measure the luminosity in low-energy stored-beam configurations. This\ncan be of great value in particular in dedicated low-energy storage rings where\nestablished methods are difficult or impossible to apply.", + "category": "nucl-ex" + }, + { + "text": "Measurements of the \u03b3* p --> \u0394(1232) reaction at low Q2: We report new p$(\\vec{e},e^\\prime p)\\pi^\\circ$ measurements in the\n$\\Delta^{+}(1232)$ resonance at the low momentum transfer region utilizing the\nmagnetic spectrometers of the A1 Collaboration at MAMI. The mesonic cloud\ndynamics are predicted to be dominant and appreciably changing in this region\nwhile the momentum transfer is sufficiently low to be able to test chiral\neffective calculations. The results disagree with predictions of constituent\nquark models and are in reasonable agreement with dynamical calculations with\npion cloud effects, chiral effective field theory and lattice calculations. The\nreported measurements suggest that improvement is required to the theoretical\ncalculations and provide valuable input that will allow their refinements.", + "category": "nucl-ex" + }, + { + "text": "Experimental Evidence of Large Collective Enhancement of Nuclear Level\n Density and its Significance in Radiative Neutron Capture: The collective enhancement of nuclear level density and its fade out with\nexcitation energy in deformed $^{171}$Yb nucleus has been inferred through an\nexclusive measurement of neutron spectra.The statistical model analysis of\nneutron spectra demonstrated a large collective enhancement factor of 40$\\pm$3\nfor the first time, which corroborates with the recent microscopic model\npredictions but is an anomalous result compared with the measurements in the\nnearby deformed nuclei. The complete picture of the energy dependent collective\nenhancement has been obtained by combining with Oslo data below neutron binding\nenergy. The significance of large collective enhancement in radiative neutron\ncapture cross section of astrophysical interest is highlighted.", + "category": "nucl-ex" + }, + { + "text": "Measurement of substructure-dependent jet suppression in Pb+Pb\n collisions at 5.02 TeV with the ATLAS detector: The ATLAS detector at the Large Hadron Collider has been used to measure jet\nsubstructure modification and suppression in Pb+Pb collisions at a\nnucleon-nucleon center-of-mass energy\n$\\sqrt{s_{_\\mathrm{NN}}}=5.02~\\mathrm{TeV}$ in comparison with $pp$ collisions\nat $\\sqrt{s}=5.02~\\mathrm{TeV}$. The Pb+Pb data, collected in 2018, have an\nintegrated luminosity of $1.72~\\mathrm{nb^{-1}}$, while the $pp$ data,\ncollected in 2017, have an integrated luminosity of $260~\\mathrm{pb}^{-1}$.\nJets used in this analysis are clustered using the anti-$k_{t}$ algorithm with\na radius parameter $R=0.4$. The jet constituents, defined by both tracking and\ncalorimeter information, are used to determine the angular scale $r_\\mathrm{g}$\nof the first hard splitting inside the jet by reclustering them using the\nCambridge-Aachen algorithm and employing the soft-drop grooming technique. The\nnuclear modification factor, $R_\\mathrm{AA}$, used to characterize jet\nsuppression in Pb+Pb collisions, is presented differentially in $r_\\mathrm{g}$,\njet transverse momentum, and in intervals of collision centrality. The\n$R_\\mathrm{AA}$ value is observed to depend significantly on jet\n$r_\\mathrm{g}$. Jets produced with the largest measured $r_\\mathrm{g}$ are\nfound to be twice as suppressed as those with the smallest $r_\\mathrm{g}$ in\ncentral Pb+Pb collisions. The $R_\\mathrm{AA}$ values do not exhibit a strong\nvariation with jet $p_\\mathrm{T}$ in any of the $r_\\mathrm{g}$ intervals. The\n$r_\\mathrm{g}$ and $p_\\mathrm{T}$ dependence of jet $R_\\mathrm{AA}$ is\nqualitatively consistent with a picture of jet quenching arising from coherence\nand provides the most direct evidence in support of this approach.", + "category": "nucl-ex" + }, + { + "text": "Mixed-symmetry octupole and hexadecapole excitations in the N=52\n isotones: Background: Excitations with mixed proton-neutron symmetry have been\npreviously observed in the $N=52$ isotones. Besides the well established\nquadrupole mixed-symmetry states (MSS), octupole and hexadecapole MSS have been\nrecently proposed for the nuclei $^{92}$Zr and $^{94}$Mo.\n Purpose: The heaviest stable $N=52$ isotone $^{96}$Ru was investigated to\nstudy the evolution of octupole and hexadecapole MSS with increasing proton\nnumber.\n Methods: Two inelastic proton-scattering experiments on $^{96}$Ru were\nperformed to extract branching ratios, multipole mixing ratios, and level\nlifetimes. From the combined data, absolute transition strengths were\ncalculated.\n Results: Strong $M1$ transitions between the lowest-lying $3^-$ and $4^+$\nstates were observed, providing evidence for a one-phonon mixed-symmetry\ncharacter of the $3^{(-)}_2$ and $4^+_2$ states.\n Conclusions: $sdg$-IBM-2 calculations were performed for $^{96}$Ru. The\nresults are in excellent agreement with the experimental data, pointing out a\none-phonon hexadecapole mixed-symmetry character of the $4^+_2$ state. The\n$\\big< 3^-_1||M1||3^{(-)}_2\\big>$ matrix element is found to scale with the\n$<2^+_{\\mathrm{s}}||M1||2^+_{\\mathrm{ms}}>$ matrix element.", + "category": "nucl-ex" + }, + { + "text": "Interpretations of Elastic Electron Scattering: Elastic scattering of relativistic electrons from the nucleon yields Lorentz\ninvariant form factors that describe the fundamental distribution of charge and\nmagnetism. The spatial dependence of the nucleon's charge and magnetism is\ntypically interpreted in the Breit reference frame which is related by a\nLorentz boost from the laboratory frame, where the nucleon is at rest. We\nconstruct a toy model to estimate how the charge and magnetic radii of the\nnucleon are modified between the Breit and lab. frames. This has implications\nfor the ratio of the proton electric to magnetic elastic form factors as a\nfunction of momentum transfer as well as for determinations of the proton\ncharge radius. Predicted corrections based on the model are provided for the\nrms charge radii of the deuteron, the triton, and the helium isotopes.", + "category": "nucl-ex" + }, + { + "text": "Antinucleus Production at RHIC: Light antinuclei may be formed in relativistic heavy ion collisions via final\nstate coalescence of antinucleons. The yields of antinuclei are sensitive to\nprimordial antinucleon production, the volume of the system at kinetic\nfreeze-out, and space-momentum correlations among antinucleons at freeze-out.\nWe report here preliminary STAR results on antideuteron and antihelion\nproduction in 130A GeV Au+Au collisions. These results are examined in a\ncoalescence framework to elucidate the space-time structure of the antinucleon\nsource.", + "category": "nucl-ex" + }, + { + "text": "High pT correlations with strange particles in STAR: We present the highlights of the current identified strange particles\nDeltaPhi and DeltaEta correlations analyses, including system-size and\ntrigger-pT of the jet and ridge, jet, ridge and away-side meson/baryon ratios,\nand the current state of the multi-strange baryon analysis. We see clear\nazimuthal peaks of comparable strength for all strange baryons and K0-short\nmesons. We see no observable species dependence on the same-side jet or ridge\nyields as a function of pT. However, while the away side and the ridge have\nLambda to K0-short ratio similar to that of the bulk, the jet-only ratio is\nsimilar to that in $p+p$. The implications of these findings on current\nin-medium jet theoretical explanations are discussed.", + "category": "nucl-ex" + }, + { + "text": "Centrality dependence of the thermal excitation-energy deposition in\n 8-15 GeV/c hadron-Au reactions: The excitation energy per residue nucleon (E*/A) and fast and thermal light\nparticle multiplicities are studied as a function of centrality defined as the\nnumber of grey tracks emitted N_grey and by the mean number of primary\nhadron-nucleon scatterings and mean impact parameter extracted from\nit. The value of E*/A and the multiplicities show an increase with centrality\nfor all systems, 14.6 GeV p-Au and 8.0 GeV pi-Au and pbar-Au collisions, and\nthe excitation energy per residue nucleon exhibits a uniform dependence on\nN_grey.", + "category": "nucl-ex" + }, + { + "text": "Inclusive Studies of Short-Range Correlations: Overview and New Results: We present an overview of Short-Range Correlations (SRC) studies using the\ninclusive measurement of the electron scattering off nuclei. A brief\nintroduction of the origin of the SRC is given, followed by the survey of the\ntwo-nucleon SRC (2N-SRC) study and its interesting connection to the EMC\neffect. A discussion of the three-nucleon SRC study (3N-SRC) measured by the\nJefferson Lab's Hall B and Hall C experiments which showed contradictory\nresults is given and, most importantly, we report a new result from the Hall A\nE08-014 experiment which was dedicated on studying 3N-SRC. Our high precision\n4He/3He cross section ratios at the x > 2 region do not show a 3N-SRC plateau\nas predicted by the naive SRC model. To further investigate the 3N-SRC as well\nas the Isospin effect of the SRC, we have designed several approved experiments\nin Hall A and in Hall C, including the Tritium experiments using the mirror\nnuclei (3H and 3He) which are currently running in Hall A.", + "category": "nucl-ex" + }, + { + "text": "The Evolution of Nuclear Multifragmentation in the Temperature-Density\n Plane: The mean transverse kinetic energies of the fragments formed in the\ninteraction of 1 A GeV Au+C have been determined. An energy balance argument\nindicates the presence of a collective energy which increases in magnitude with\nincreasing multiplicity and accounts for nearly half of the measured mean\ntransverse kinetic energy. The radial flow velocity associated with the\ncollective energy yields estimates for the time required to expand to the\nfreeze-out volume. Isentropic trajectories in the temperature-density plane are\nshown for the expansion and indicate that the system goes through the critical\nregion at the same multiplicities as deduced from a statistical analysis. Here,\nthe expansion time is approximately 70 fm/c.", + "category": "nucl-ex" + }, + { + "text": "Flavor Decomposition of Nucleon Form Factors: The nucleon form factors provide fundamental knowledge about the strong\ninteraction. We review the flavor composition of the nucleon form factors and\nfocus on an analysis of the possible impact of the s-quark contribution. A\nfuture experiment is presented to measure the strange form factor at large\nmomentum transfer.", + "category": "nucl-ex" + }, + { + "text": "Jefferson Lab Science, Past and Future: The Continuous Electron Beam Accelerator Facility (CEBAF) and associated\nexperimental equipment at Jefferson Lab comprise a unique facility for\nexperimental nuclear physics. This facility is presently being upgraded, which\nwill enable a new experimental program with substantial discovery potential to\naddress important topics in nuclear, hadronic, and electroweak physics. Further\nin the future, it is envisioned that the Laboratory will evolve into an\nelectron-ion colliding beam facility.", + "category": "nucl-ex" + }, + { + "text": "Separated Response Functions in Exclusive, Forward $\u03c0^{\\pm}$\n Electroproduction on Deuterium: Background: Measurements of forward exclusive meson production at different\nsquared four-momenta of the exchanged virtual photon, $Q^2$, and at different\nfour-momentum transfer, t, can be used to probe QCD's transition from\nmeson-nucleon degrees of freedom at long distances to quark-gluon degrees of\nfreedom at short scales. Ratios of separated response functions in $\\pi^-$ and\n$\\pi^+$ electroproduction are particularly informative. The ratio for\ntransverse photons may allow this transition to be more easily observed, while\nthe ratio for longitudinal photons provides a crucial verification of the\nassumed pole dominance, needed for reliable extraction of the pion form factor\nfrom electroproduction data. Method: Data were acquired with 2.6-5.2 GeV\nelectron beams and the HMS+SOS spectrometers in Jefferson Lab Hall C, at\ncentral $Q^2$ values of 0.6, 1.0, 1.6 GeV$^2$ at W=1.95 GeV, and $Q^2$=2.45\nGeV$^2$ at W=2.22 GeV. There was significant coverage in $\\phi$ and $\\epsilon$,\nwhich allowed separation of $\\sigma_{L,T,LT,TT}$. Results: $\\sigma_L$ shows a\nclear signature of the pion pole, with a sharp rise at small -t. In contrast,\n$\\sigma_T$ is much flatter versus t. The longitudinal/transverse ratios evolve\nwith $Q^2$ and t, and at the highest $Q^2$=2.45 GeV$^2$ show a slight\nenhancement for $\\pi^-$ production compared to $\\pi^+$. The $\\pi^-/\\pi^+$ ratio\nfor transverse photons exhibits only a small $Q^2$-dependence, following a\nnearly universal curve with t, with a steep transition to a value of about\n0.25, consistent with s-channel quark knockout. The $\\sigma_{TT}/\\sigma_T$\nratio also drops rapidly with $Q^2$, qualitatively consistent with s-channel\nhelicity conservation. The $\\pi^-/\\pi^+$ ratio for longitudinal photons\nindicates a small isoscalar contamination at W=1.95 GeV, consistent with what\nwas observed in our earlier determination of the pion form factor at these\nkinematics.", + "category": "nucl-ex" + }, + { + "text": "Charged-particle jet spectra in event-shape engineered Pb--Pb collisions\n at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV with ALICE: The path-length dependence of jet quenching can help to constrain different\njet quenching mechanisms in heavy-ion collisions. However, measuring an\nexplicit value for this dependence has proven challenging. Traditional\napproaches, which consider anisotropic jet suppression arising from geometric\nasymmetries, have successfully measured a non-zero azimuthal dependence of jet\nmodification with respect to the event-plane angle of the collision. While such\nsignals improve our qualitative understanding of this topic, extraction of an\nexplicit dependence from these results is limited by fluctuations in the\ninitial state and jet--medium interactions. A new approach to characterize the\ngeometry of the collision is to use event-shape engineering, a technique that\nclassifies events within a centrality class according to their elliptical\nanisotropies. By doing so, we gain an improved knowledge of the initial-state\nmedium, consequently enabling better constraints on the average path length\ntraversed by the jet. In these proceedings, new results of jet spectra from\nevent-shape-engineered collisions at ALICE will be presented.", + "category": "nucl-ex" + }, + { + "text": "On the transverse momentum distribution of strange hadrons produced in\n relativistic heavy ion collisions: Particles with strange quark content produced in the system 1.93 AGeV\n$^{58}$Ni on $^{58}$Ni have been investigated at GSI Darmstadt with the FOPI\ndetector system. The correlation of these produced particles was analyzed with\nrespect to the reaction plane. Lambda baryons exhibit a very pronounced\nsideward flow pattern which is qualitatively similar to the proton flow.\nHowever, the kaon ($K^+$,$K^0_S$) flow patterns are significantly different\nfrom that of the protons, and their form may be useful to restrict theoretical\nmodels on the form of the kaon potential in the nuclear medium.", + "category": "nucl-ex" + }, + { + "text": "Exploring the Partonic Structure of Hadrons through the Drell-Yan\n Process: The Drell-Yan process is a standard tool for probing the partonic structure\nof hadrons. Since the process proceeds through a quark-antiquark annihilation,\nDrell-Yan scattering possesses a unique ability to selectively probe sea\ndistributions. This review examines the application of Drell-Yan scattering to\nelucidating the flavor asymmetry of the nucleon's sea and nuclear modifications\nto the sea quark distributions in unpolarized scattering. Polarized beams and\ntargets add an exciting new dimension to Drell-Yan scattering. In particular,\nthe two initial-state hadrons give Drell-Yan sensitivity to chirally-odd\ntransversity distributions.", + "category": "nucl-ex" + }, + { + "text": "Weak interaction studies at SARAF: We review the current status of the radioisotopes program at the Soreq\nApplied Research Accelerator Facility (SARAF), where we utilize an\nelectrostatic-ion-beam trap and a magneto-optical trap for studying the nuclear\n$\\beta$-decay from trapped radioactive atoms and ions. The differential energy\nspectra of $\\beta$'s and recoil ions emerging from the decay is sensitive to\nbeyond standard model interactions and is complementary to high energy\nsearches. The completed facility SARAF-II will be one of the world's most\npowerful deuteron, proton and fast neutron sources, producing light radioactive\nisotopes in unprecedented amounts, needed for obtaining enough statistics for a\nhigh precision measurement.", + "category": "nucl-ex" + }, + { + "text": "Measurement of long-range two-particle azimuthal correlations in\n $Z$-boson tagged $pp$ collisions at $\\sqrt{s}{=}8$ and 13 TeV: Results are presented from the measurement by ATLAS of long-range\n($|\\Delta\\eta|>2$)dihadron angular correlations in $\\sqrt{s}=8$ and 13 TeV $pp$\ncollisions containing a $Z$ boson. The analysis is performed using 19.4\n$\\mathrm{fb}^{-1}$ of $\\sqrt{s}=8$ TeV data recorded during Run 1 of the LHC\nand 36.1 $\\mathrm{fb}^{-1}$ of $\\sqrt{s}=13$ TeV data recorded during Run 2.\nTwo-particle correlation functions are measured as a function of relative\nazimuthal angle over the relative pseudorapidity range $2<|\\Delta\\eta|<5$ for\ndifferent intervals of charged-particle multiplicity and transverse momentum.\nThe measurements are corrected for the presence of background charged particles\ngenerated by collisions that occur during one passage of two colliding proton\nbunches in the LHC. Contributions to the two-particle correlation functions\nfrom hard processes are removed using a template-fitting procedure. Sinusoidal\nmodulation in the correlation functions is observed and quantified by the\nsecond Fourier coefficient of the correlation function, $v_{2,2}$, which in\nturn is used to obtain the single-particle anisotropy coefficient $v_{2}$. The\n$v_{2}$ values in the $Z$-tagged events, integrated over $0.510$ GeV/$c$, whereas for lower\n$p_{\\rm T}^{\\rm trig}$ values the event activity is slightly higher in p$-$Pb\nthan in pp collisions. The measurements are compared with predictions from the\nPYTHIA 8 and EPOS LHC Monte Carlo event generators.", + "category": "nucl-ex" + }, + { + "text": "Inelastic Scatterings of Entangled Mossbauer Gammas: We report the observation of the temperature-dependent inelastic scattering\nof three entangled Mossbauer gammas in the time-resolved Mossbauer\nspectroscopy. Recently, the long-lived E3 Mossbauer transition of rhodium\ngenerated by bremsstrahlung irradiation has been reported. Two kinds of X-rays\nwith the fast decay are attributed to the tri-photon effect. They are\ntri-photon pile-up of rhodium K X-rays and the high-Z impurity K X-rays. Energy\nof the particular K emission is higher than the sum energy of two Mossbauer\ngammas. This letter reports new discoveries by cooling down the sample using\nliquid nitrogen, namely the collective anomalous emission of entangled\nMossbauer gammas. The enhancement of inelastic scatterings at low temperature\nsuch as rhodium K satellites is attributed to this entanglement.", + "category": "nucl-ex" + }, + { + "text": "Evidence on the absence of critical transition in AMPT for Pb-Pb\n collisions at $sqrt{s_{\\rm{NN}}}$ = 2.76 TeV: Event-by-event fluctuations in the spatial patterns in charged particles\ngenerated in Pb--Pb collisions at the center-of-mass energy\n$\\sqrt{S_{\\rm{NN}}}$ = 2.76 TeV are studied within A MultiPhase Transport\n(AMPT) model. The spatial patterns of the particles generated in the ($\\eta,\n\\phi$) space for $|\\eta| \\le 0.8$ are studied using the methodology of\nintermittency and erraticity analysis. We find negative intermittency for\ncharged particles generated in a range of $p_{\\rm{T}}$ windows. This result\ncontrasts sharply from what is expected for a quark-gluon plasma undergoing\nhadronization by a second-order phase transition. Appropriate scaling behavior\nis examined, resulting in definitive scaling exponent $\\nu_{-}$. Event-by-event\nfluctuations in the spatial patterns quantified by an index, named erraticity\nindex are determined for different $p_{\\rm{T}}$ bins $\\leq 1$ GeV/c, for AMPT\nmodel. This is the first time that the intermittency and erraticity indices are\ndetermined for any model at such high energies. The results presented here can\nbe used for comparison with the fluctuation properties of the experimental data\nand hence can help the development of a wider scope of understanding of\nvalidity of the particle production process by AMPT at these energies on the\none hand, and of the true nature of the real data on the other.", + "category": "nucl-ex" + }, + { + "text": "Direct determination of the excitation energy of quasi-stable isomer\n $^{180m}$Ta: $^{180m}$Ta is a naturally abundant quasi-stable nuclide and the\nlongest-lived nuclear isomer known to date. It is of interest for, among\nothers, the search for dark matter, for the development of a gamma laser and\nfor astrophysics. So far, its excitation energy has not been measured directly\nbut has been based on an evaluation of available nuclear reaction data. We have\ndetermined the excitation energy of this isomer with high accuracy using the\nPenning-trap mass spectrometer JYFLTRAP. The determined mass difference between\nthe ground and isomeric states of $^{180}$Ta yields an excitation energy of\n76.79(55) keV for $^{180m}$Ta. This is the first direct measurement of the\nexcitation energy and provides a better accuracy than the previous evaluation\nvalue, 75.3(14) keV.", + "category": "nucl-ex" + }, + { + "text": "Observation of flow angle and flow magnitude fluctuations in Pb-Pb\n collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV at the CERN Large Hadron\n Collider: This Letter reports on the first measurements of transverse momentum\ndependent flow angle $\\Psi_n$ and flow magnitude $v_n$ fluctuations, determined\nusing new four-particle correlators. The measurements are performed for various\ncentralities in Pb-Pb collisions at a centre-of-mass energy per nucleon pair of\n$\\sqrt{s_{\\rm NN}}$ = 5.02 TeV with ALICE at the CERN Large Hadron Collider.\nBoth flow angle and flow magnitude fluctuations are observed in the presented\ncentrality ranges and are strongest in the most central collisions and for a\ntransverse momentum $p_{\\rm T}>2$ GeV/$c$. Comparison with theoretical models,\nincluding iEBE-VISHNU, MUSIC, and AMPT, show that the measurements exhibit\nunique sensitivities to the initial state of heavy-ion collisions.", + "category": "nucl-ex" + }, + { + "text": "Neutron capture of 26Mg at thermonuclear energies: The neutron capture cross section of 26Mg was measured relative to the known\ngold cross section at thermonuclear energies using the fast cyclic activation\ntechnique. The experiment was performed at the 3.75 MV Van-de-Graaff\naccelerator, Forschungszentrum Karlsruhe. The experimental capture cross\nsection is the sum of resonant and direct contributions. For the resonance at\nE(n,lab) = 220 keV our new results are in disagreement with the data from\nWeigmann et al. An improved Maxwellian averaged capture cross section is\nderived from the new experimental data taking into account s- and p-wave\ncapture and resonant contributions. The properties of so-called potential\nresonances which influence the p-wave neutron capture of 26}Mg are discussed in\ndetail.", + "category": "nucl-ex" + }, + { + "text": "Event anisotropy $v_{2}$ in Au+Au collisions at $\\sqrt{s_{NN}}=$ 7.7 -\n 62.4 GeV with STAR: We present the $v_2$ measurement at midrapidity from Au+Au collisions at\n$\\sqrt{s_{NN}}=$ 7.7, 11.5, 19.6, 27, 39 and 62.4 GeV for inclusive charged\nhadrons and identified hadrons ($\\pi^{\\pm}$, $K^{\\pm}$, $K_{S}^{0}$, $p$,\n$\\bar{p}$, $\\phi$, $\\Lambda$, $\\bar{\\Lambda}$, $\\Xi^{-}$, $\\bar{\\Xi}^{+}$,\n$\\Omega^{-}$, $\\bar{\\Omega}^{+}$) up to 4 GeV/$c$ in $p_{T}$. The beam energy\nand centrality dependence of charged hadron $v_2$ are presented with comparison\nto higher energies at RHIC and LHC. The identified hadron $v_{2}$ are used to\ndiscuss the NCQ scaling for different beam energies. Significant difference in\n$v_{2}(p_{T})$ is observed between particles and corresponding anti-particles\nfor $\\sqrt{s_{NN}} <$ 39 GeV. These differences are more pronounced for baryons\ncompared to mesons and they increase with decreasing energy.", + "category": "nucl-ex" + }, + { + "text": "Identified particle transverse momentum spectra in p+p and d+Au\n collisions at sqrt{s_NN} = 200 GeV: The transverse momentum ($p_{\\mathrm T}$) spectra for identified charged\npions, protons and anti-protons from $p$+$p$ and $d$+Au collisions are measured\naround midrapidity ($\\mid$y$\\mid$ $<$ 0.5) over the range of 0.3 $<$\n$p_{\\mathrm T}$ $<$ 10 GeV/$c$ at $\\sqrt{s_{\\mathrm {NN}}}$ = 200 GeV. The\ncharged pion and proton+anti-proton spectra at high p_{T} in p+p collisions\nhave been compared with the next-to-leading order perturbative quantum\nchromodynamic (NLO pQCD) calculations with a specific fragmentation scheme. The\np/pi^{+} and pbar/pi^{-}has been studied at high p_{T}. The nuclear\nmodification factor (R_{dAu}) shows that the identified particle Cronin effects\naround midrapidity are significantly non-zero for charged pions and to be even\nlarger for protons at intermediate p_{T} (2 < p_{T} < 5 GeV/c).", + "category": "nucl-ex" + }, + { + "text": "Magnetic and antimagnetic rotational bands data tables: The experimental results of 252 magnetic rotational bands reported in 123\nnuclei and 38 antimagnetic rotational bands reported in 27 nuclei are collected\nand listed in the present work, including energy, spin, parity, magnetic dipole\nreduced transition probability B(M1), electric quadrupole reduced transition\nprobability B(E2), B(M1)/B(E2) ratio, and the ratio of the dynamic moment of\ninertia to the electric quadrupole reduced transition probability J(2)/B(E2).\nFollowing the presentation of the kinematic moment of inertia J(1), dynamic\nmoment of inertia J(2), and I versus rotational frequency, as well as energy\nstaggering parameter S(I), B(M1), B(E2), B(M1)/B(E2), and J(2)/B(E2) versus I\nin A 60, 80, 110, 140, and 190 mass regions, a brief discussion is provided.\nBased on the systematic studies, some nuclei are predicted to be candidates for\nmagnetic or antimagnetic rotation.", + "category": "nucl-ex" + }, + { + "text": "High Precision Measurement of the Proton Elastic Form Factor Ratio at\n Low $Q^2$: Jefferson Lab experiment E08-007 measured the proton elastic form factor\nratio $\\mu_pG_E/G_M$ in the range of $Q^2=0.3-0.7(\\mathrm{GeV}/c)^2$ by recoil\npolarimetry. Data were taken in 2008 at the Thomas Jefferson National\nAccelerator Facility in Virginia, USA. A 1.2 GeV polarized electron beam was\nscattered off a cryogenic hydrogen target. The recoil proton was detected in\nthe left HRS in coincidence with the elasticly scattered electrons tagged by\nthe BigBite spectrometer. The proton polarization was measured by the focal\nplane polarimeter (FPP). In this low $Q^2$ region, previous measurement from\nJefferson Lab Hall A (LEDEX) along with various fits and calculations indicate\nsubstantial deviations of the ratio from unity. For this new measurement, the\nproposed statistical uncertainty ($<1%$) was achieved. These new results are a\nfew percent lower than expected from previous world data and fits, which\nindicate a smaller $G_{Ep}$ at this region. Beyond the intrinsic interest in\nnucleon structure, the new results also have implications in determining the\nproton Zemach radius and the strangeness form factors from parity violation\nexperiments.", + "category": "nucl-ex" + }, + { + "text": "Search for $\u03b7$-mesic nuclei in recoil-free transfer reaction: We have studied the reaction $p+{^{27}Al}\\to {^3{He}}+p+\\pi^-+X$ at\nrecoil-free kinematics. An $\\eta$ meson possibly produced in this reaction\nwould be thus almost at rest in the laboratory system and could therefore be\nbound with high probability, if nuclear $\\eta$ states exist. The decay of such\na state through the $N^*(1535)$ resonance would lead to a proton-$\\pi^-$ pair\nemitted in opposite directions. For these conditions we find some indication of\nsuch a bound state. An upper limit of $\\approx$ 0.5 nb is found.", + "category": "nucl-ex" + }, + { + "text": "The Challenge of the EMC Effect: existing data and future directions: Since the discovery that the ratio of inclusive charged lepton (per-nucleon)\ncross sections from a nucleus A to the deuteron is not unity - even in deep\ninelastic scattering kinematics - a great deal of experimental and theoretical\neffort has gone into understanding the phenomenon. The EMC effect, as it is now\nknown, shows that even in the most extreme kinematic conditions the effects of\nthe nucleon being bound in a nucleus can not be ignored. In this paper we\ncollect the most precise data available for various nuclear to deuteron ratios,\nas well as provide a commentary on the current status of the theoretical\nunderstanding of this thirty year old effect.", + "category": "nucl-ex" + }, + { + "text": "Thermal photon measurements at PHENIX: Photons are emitted at all stages of relativistic heavy-ion collisions and do\nnot interact with the medium strongly. With access to the versatility of RHIC,\nmeasurements of low momentum direct photons are made possible across different\nsystem size and beam energies. An excess of direct photons, above prompt photon\nproduction from hard scattering processes, is observed for a system size\ncorresponding to $dN_{ch}/d\\eta$ of 20-30, with a large azimuthal anisotropy\nand a characteristic dependence on collision centrality. After subtracting the\nprompt photon component, the inverse slope of the spectrum is continuously\nincreasing with the effective temperature ranging from 250 MeV/c at $p_{T}$ of\n1-2 GeV/c to about 400 MeV/c at 2-4 GeV/c. Within the experimental uncertainty,\nthere is no indication of a system size dependence of the inverse slope. In\nthis proceeding, results from Au+Au collisions from the PHENIX experiment will\nbe presented.", + "category": "nucl-ex" + }, + { + "text": "Noise Equivalent Counts Based Emission Image Reconstruction Algorithm of\n Tomographic Gamma Scanning: Tomographic Gamma Scanning (TGS) is a technique used to assay the nuclide\ndistribution and radioactivity in nuclear waste drums. Both transmission and\nemission scans are performed in TGS and the transmission image is used for the\nattenuation correction in emission reconstructions. The error of the\ntransmission image, which is not considered by the existing reconstruction\nalgorithms, negatively affects the final results. An emission reconstruction\nmethod based on Noise Equivalent Counts (NEC) is presented. Noises from the\nattenuation image are concentrated to the projection data to apply the NEC\nMaximum-Likelihood Expectation-Maximization algorithm. Experiments are\nperformed to verify the effectiveness of the proposed method.", + "category": "nucl-ex" + }, + { + "text": "Analysis of Experiments Exhibiting Time-Varying Nuclear Decay Rates:\n Systematic Effects or New Physics?: Since the 1930s, and with very few exceptions, it has been assumed that the\nprocess of radioactive decay is a random process, unaffected by the environment\nin which the decaying nucleus resides. There have been instances within the\npast few decades, however, where changes in the chemical environment or\nphysical environment brought about small changes in the decay rates. But even\nin light of these instances, decaying nuclei that were undisturbed or\nun-\"pressured\" were thought to behave in the expected random way, subject to\nthe normal decay probabilities which are specific to each nuclide. Moreover,\nany \"non-random\" behavior was assumed automatically to be the fault of the\ndetection systems, the environment surrounding the detectors, or changes in the\nbackground radiation to which the detector was exposed. Recently, however,\nevidence has emerged from a variety of sources, including measurements taken by\nindependent groups at Brookhaven National Laboratory, Physikalisch-Technische\nBundesanstalt, and Purdue University, that indicate there may in fact be an\ninfluence that is altering nuclear decay rates, albeit at levels on the order\nof $10^{-3}$. In this paper, we will discuss some of these results, and examine\nthe evidence pointing to the conclusion that the intrinsic decay process is\nbeing affected by a solar influence.", + "category": "nucl-ex" + }, + { + "text": "Study of the hadron gas phase using short-lived resonances with ALICE: Short-lived hadronic resonances are unique tools for studying the hadron-gas\nphase that is created in the late stages of relativistic heavy-ion collisions.\nMeasurements of the yield ratios between resonances and the corresponding\nstable particles are sensitive to the competing rescattering and regeneration\neffects. These measurements in small collision systems, such as pp and p-Pb,\nare a powerful method to reveal a possible short-lived hadronic phase. In\naddition, resonance production in small systems is interesting to study the\nonset of strangeness enhancement, collective effects,and the hadron production\nmechanism. On this front, the $\\phi$ meson is particularly relevant since its\nyield is sensitive to different production models: no effect is expected by\nstrange number canonical suppression but its production is expected to be\nenhanced in the rope-hadronization scenario. In this presentation, recent\nmeasurements of hadronic resonances in different collision systems,going from\npp to Pb-Pb collisions, are presented. These include transverse momentum\nspectra,yields, and yield ratios as a function of multiplicity. The presented\nresults are discussed in the context of state-of-the-art phenomenological\nmodels of hadron production. The resonance yields measured in Pb-Pb collisions\nare used as an experimental input in a partial chemical equilibrium-based\nthermal model to constrain the kinetic freeze-out temperature. This is a novel\nprocedure that is independent of assumptions on the flow velocity profile and\nthe freeze-out hypersurface.", + "category": "nucl-ex" + }, + { + "text": "Enhanced Production of Low-Mass Electron Pairs in 40 AGeV Pb-Au\n Collisions at the CERN SPS: We report on first measurements of low-mass electron pairs in Pb-Au\ncollisions at the lower SPS beam energy of 40 AGeV. The pair yield integrated\nover the range of invariant masses 0.2 e+ e- annihilation with a modified rho-propagator. They may be linked to\nchiral symmetry restoration and support the notion that the in-medium\nmodifications of the rho are more driven by baryon density than by temperature.", + "category": "nucl-ex" + }, + { + "text": "The $^{15}$O($\u03b1$,$\u03b3$)$^{19}$Ne Breakout Reaction and Impact on\n X-Ray Bursts: The breakout reaction $^{15}$O($\\alpha,\\gamma$)$^{19}$Ne, which regulates the\nflow between the hot CNO cycle and the rp-process, is critical for the\nexplanation of the burst amplitude and periodicity of X-ray bursters. We report\non the first successful measurement of the critical $\\alpha$-decay branching\nratios of relevant states in $^{19}$Ne populated via\n$^{19}$F($^3$He,t)$^{19}$Ne. Based on the experimental results and our previous\nlifetime measurements of these states, we derive the first experimental rate of\n$^{15}$O($\\alpha,\\gamma$)$^{19}$Ne. The impact of our experimental results on\nthe burst pattern and periodicity for a range of accretion rates is analyzed.", + "category": "nucl-ex" + }, + { + "text": "Higher-twist analysis of moments of spin structure function: Available analyses on moments of the spin structure function g_1 use\ndifferent methods and are barely consistent with each other. We present a\nhigher twist analysis of Gamma_1^p using a method consistent with the studies\nof Gamma_1^n and Gamma_1^(p-n) already published. The twist-4 coefficient f_2\nis extracted. One result is that the higher twist coefficients seem to\nalternate signs: the relatively larger twist-6 contribution is partly\nsuppressed by the twist-4 and twist-8 contributions. The size of twist-6 can be\ndue to the elastic contribution to the moments.", + "category": "nucl-ex" + }, + { + "text": "Advances and new ideas for neutron-capture astrophysics experiments at\n CERN n_TOF: This article presents a few selected developments and future ideas related to\nthe measurement of $(n,\\gamma)$ data of astrophysical interest at CERN n_TOF.\nThe MC-aided analysis methodology for the use of low-efficiency radiation\ndetectors in time-of-flight neutron-capture measurements is discussed, with\nparticular emphasis on the systematic accuracy. Several recent instrumental\nadvances are also presented, such as the development of total-energy detectors\nwith $\\gamma$-ray imaging capability for background suppression, and the\ndevelopment of an array of small-volume organic scintillators aimed at\nexploiting the high instantaneous neutron-flux of EAR2. Finally, astrophysics\nprospects related to the intermediate $i$ neutron-capture process of\nnucleosynthesis are discussed in the context of the new NEAR activation area.", + "category": "nucl-ex" + }, + { + "text": "Identified particle measurements at RHIC: elucidating hadronization\n mechanisms for bulk partonic matter: Measurements of identified particle momentum spectra at center of mass energy\n200 GeV are reviewed. Emphasis is placed on the azimuthal dependence and the\ncentrality dependence of hadron yields at intermediate transverse momentum (1.5\n< p_T < 5 GeV/c). The first measurements of the fourth harmonic term (v_4) in\nthe azimuthal variation of identified particle yields are shown. The\nrecombination mechanism of hadron formation provides a consistent description\nof the dependence of these measurements on particle-type.", + "category": "nucl-ex" + }, + { + "text": "$\u03c0/K/p$ production and Cronin effect from p+p, d+Au and Au+Au\n collisions at $\\sqrt{s_{NN}}= 200$ GeV from the PHENIX experiment: We present results on identified particle production in p+p, d+Au and Au+Au\ncollisions at $\\sqrt{s_{NN}} = 200$ GeV at mid-rapidity measured by the PHENIX\nexperiment. The centrality and flavor dependence of the Cronin effect in d+Au\ncollisions is measured. The Cronin effect for the protons in d+Au is larger\nthan that for the pions, but not large enough to account for the ``anomalous''\nproton to pion ratio in central Au+Au collisions.", + "category": "nucl-ex" + }, + { + "text": "Hadrons in the Nuclear Medium -- Quarks, Nucleons, or a Bit of Both?: Quantum Chromodynamics (QCD) is the theory governing the strong interaction\nof particles. It describes the interactions that bind quarks and gluons into\nprotons and neutrons, and binds these into nuclei. We believe QCD to be as\nfundamental and complete as QED, the theory of electromagnetic interactions,\nwhose predictions have been tested to more than ten decimal places. If it were\npossible to make calculations in QCD the same way we can in QED, we would have\nremoved one of the biggest obstacles in the way of understanding matter in the\nuniverse. Unfortunately, the properties of QCD make such calculations\nimpossible at present. Historically, there have been two approaches to this\nproblem. First, we work to improve our ability to solve QCD, with the most\nvisible effort being the field of Lattice QCD. Second, we make models of QCD\nthat attempt to incorporate what we believe to be the most important\nsymmetries, dynamics, or degrees of freedom, and then test these models against\nexperimental measurements sensitive to these assumptions. Even the earliest\nquark models of hadrons structure and the simplest bag models have had great\nsuccess, far beyond any reasonable expectation, indicating that these models\nhave isolated some of the key features of QCD. More detailed models and ever\nmore sophisticated experimental tests are significantly improving such details,\nand helping to better identify the most relevant features of QCD, one of the\nkey missing pieces in our understanding of the nature of matter.", + "category": "nucl-ex" + }, + { + "text": "Nonfuel Antineutrino Contributions in the High Flux Isotope Reactor: Reactor neutrino experiments have seen major improvements in precision in\nrecent years. With the experimental uncertainties becoming lower than those\nfrom theory, carefully considering all sources of $\\overline{\\nu}_{e}$ is\nimportant when making theoretical predictions. One source of\n$\\overline{\\nu}_{e}$ that is often neglected arises from the irradiation of the\nnonfuel materials in reactors. The $\\overline{\\nu}_{e}$ rates and energies from\nthese sources vary widely based on the reactor type, configuration, and\nsampling stage during the reactor cycle and have to be carefully considered for\neach experiment independently. In this article, we present a formalism for\nselecting the possible $\\overline{\\nu}_{e}$ sources arising from the neutron\ncaptures on reactor and target materials. We apply this formalism to the High\nFlux Isotope Reactor (HFIR) at Oak Ridge National Laboratory, the\n$\\overline{\\nu}_{e}$ source for the the Precision Reactor Oscillation and\nSpectrum Measurement (PROSPECT) experiment. Overall, we observe that the\nnonfuel $\\overline{\\nu}_{e}$ contributions from HFIR to PROSPECT amount to 1\\%\nabove the inverse beta decay threshold with a maximum contribution of 9\\% in\nthe 1.8--2.0~MeV range. Nonfuel contributions can be particularly high for\nresearch reactors like HFIR because of the choice of structural and reflector\nmaterial in addition to the intentional irradiation of target material for\nisotope production. We show that typical commercial pressurized water reactors\nfueled with low-enriched uranium will have significantly smaller nonfuel\n$\\overline{\\nu}_{e}$ contribution.", + "category": "nucl-ex" + }, + { + "text": "Quest for a Nuclear Georeactor: Knowledge about the interior of our planet is mainly based on the\ninterpretation of seismic data from earthquakes and nuclear explosions, and of\ncomposition of meteorites. Additional observations have led to a wide range of\nhypotheses on the heat flow from the interior to the crust, the abundance of\ncertain noble gases in gasses vented from volcanoes and the possibility of a\nnuclear georeactor at the centre of the Earth. This paper focuses on a proposal\nfor an underground laboratory to further develop antineutrinos as a tool to map\nthe distribution of radiogenic heat sources, such as the natural radionuclides\nand the hypothetical nuclear georeactor.", + "category": "nucl-ex" + }, + { + "text": "Observation of Pendell\u00f6sung Fringes by Using Pulsed Neutrons: Pendell\\\"{o}sung interference fringes of a single silicon crystal were\nobserved by using pulsed cold neutrons. The nuclear scattering length of\nsilicon was obtained as (4.159\\pm0.003(stat.)\\pm0.028(syst.)) fm using the\nobserved Pendell\\\"{o}sung fringes. This indicates the applicability of pulsed\nneutron beam to observe the Pendell\\\"{o}sung fringes by using the\ntime-of-flight analysis.", + "category": "nucl-ex" + }, + { + "text": "The 95zr(n, gamma)96zr cross section from the surrogate ratio method and\n its effect on the s-process nucleosynthesis: The 95Zr(n,gamma)96Zr reaction cross section is crucial in the modelling of\ns-process nucleosynthesis in asymptotic giant branch stars because it controls\nthe operation of the branching point at the unstable 95Zr and the subsequent\nproduction of 96Zr. We have carried out the measurement of the 94Zr(18O,16O)\nand 90Zr(18O,16O) reactions and obtained the gamma-decay probability ratio of\n96Zr* and 92Zr* to determine the 95Zr(n,gamma)96Zr reaction cross sections with\nthe surrogate ratio method. Our deduced maxwellian-averaged cross section of\n66+-16 mb at 30 keV is close to the value recommended by Bao et al. (2000), but\n30% and more than a factor of two larger than the values proposed by Toukan &\nKappeler (1990) and Lugaro et al. (2014), respectively, and routinely used in\ns-process models. We tested the new rate in stellar models with masses between\n2 and 6 Msun and metallicities 0.014 and 0.03. The largest changes - up 80%\nvariations in 96Zr - are seen in models of mass 3-4 Msun, where the 22Ne\nneutron source is mildly activated. The new rate can still provide a match to\ndata from meteoritic stardust silicon carbide grains, provided the maximum mass\nof the parent stars is below 4 Msun, for a metallicity of 0.03.", + "category": "nucl-ex" + }, + { + "text": "Investigation of production cross sections, using stacked targets at the\n 88\" Cyclotron with focus on $^{\\rm nat}{\\rm Fe}(\\rm p,x)^{51}{\\rm Mn}$: With the investigation of the production cross section of $\\ ^{51}\\rm Mn$ off\nof $\\ ^{\\rm nat}\\rm Fe$ in mind, two stacked target experiments were conducted\nat the Berkeley Lab 88-Inch Cyclotron. Proton beams with energies of $25$ and\n$55\\,\\rm MeV$ result in a total of 14 data points for various reactions. Gamma\nspectra of the activated foils were taken and analyzed, then cross sections\ncalculated.", + "category": "nucl-ex" + }, + { + "text": "critRHIC: The RHIC Low Energy Program: Recent experimental and theoretical developments have motivated interest in a\nmore detailed exploration of heavy ion collisions in the range sqrt(sNN)=5-15\nGeV. In contrast to interactions at the full RHIC energy of sqrt(sNN)=200 GeV,\nsuch collisions result in systems characterized by much higher baryon chemical\npotential, muB. Extensions of lattice QCD calculations to non-zero values of\nmuB suggest that a critical point may exist in this region of the QCD phase\ndiagram. Discovery of the critical point or, equivalently, determining the\nlocation where the phase transition from partonic to hadronic matter switches\nfrom a smooth crossover to 1st order would establish a major landmark in the\nphase diagram. Initial studies of Pb+Pb collisions in this energy range have\nrevealed several unexpected features in the data. In response to these results,\nit has been suggested that the existing RHIC accelerator and experiments can be\nused to further the investigation of this important physics topic. This\nproceeding briefly summarizes the theoretical and experimental situation with\nparticular emphasis on the conclusions from a RIKEN BNL workshop held in March\nof 2006.", + "category": "nucl-ex" + }, + { + "text": "First Measurement of $\u039b$ Electroproduction off Nuclei in the\n Current and Target Fragmentation Regions: We report results of $\\Lambda$ hyperon production in semi-inclusive\ndeep-inelastic scattering off deuterium, carbon, iron, and lead targets\nobtained with the CLAS detector and the Continuous Electron Beam Accelerator\nFacility 5.014~GeV electron beam. These results represent the first\nmeasurements of the $\\Lambda$ multiplicity ratio and transverse momentum\nbroadening as a function of the energy fraction~($z$) in the current and target\nfragmentation regions. The multiplicity ratio exhibits a strong suppression at\nhigh~$z$~and~an enhancement at~low~$z$. The measured transverse momentum\nbroadening is an order of magnitude greater than that seen for light mesons.\nThis indicates that the propagating entity interacts very strongly with the\nnuclear medium, which suggests that propagation of diquark configurations in\nthe nuclear medium takes place at least part of the time, even at high~$z$. The\ntrends of these results are qualitatively described by the Giessen\nBoltzmann-Uehling-Uhlenbeck transport model, particularly for the multiplicity\nratios. These observations will potentially open a new era of studies of the\nstructure of the nucleon as well as of strange baryons.", + "category": "nucl-ex" + }, + { + "text": "Anisotropic flow and flow fluctuations of identified hadrons in Pb$-$Pb\n collisions at $\\sqrt{s_{\\mathrm{NN}}}$ = 5.02 TeV: The first measurements of elliptic flow of $\\pi^\\pm$, ${\\rm K}^\\pm$,\np+$\\overline{\\rm p}$, ${\\rm K_{S}^0}$, $\\Lambda$+$\\overline{\\Lambda}$, $\\phi$,\n$\\Xi^-$+$\\Xi^+$, and $\\Omega^-$+$\\Omega^+$ using multiparticle cumulants in\nPb$-$Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV are presented. Results\nobtained with two- ($v_2\\{2\\}$) and four-particle cumulants ($v_2\\{4\\}$) are\nshown as a function of transverse momentum, $p_{\\rm T}$, for various collision\ncentrality intervals. Combining the data for both $v_2\\{2\\}$ and $v_2\\{4\\}$\nalso allows us to report the first measurements of the mean elliptic flow,\nelliptic flow fluctuations, and relative elliptic flow fluctuations for various\nhadron species. These observables probe the event-by-event eccentricity\nfluctuations in the initial state and the contributions from the dynamic\nevolution of the expanding quark-gluon plasma. The characteristic features\nobserved in previous $p_{\\rm T}$-differential anisotropic flow measurements for\nidentified hadrons with two-particle correlations, namely the mass ordering at\nlow $p_{\\rm T}$ and the approximate scaling with the number of constituent\nquarks at intermediate $p_{\\rm T}$, are similarly present in the four-particle\ncorrelations and the combinations of $v_2\\{2\\}$ and $v_2\\{4\\}$. In addition, a\nparticle species dependence of flow fluctuations is observed that could\nindicate a significant contribution from final state hadronic interactions. The\ncomparison between experimental measurements and CoLBT model calculations,\nwhich combine the various physics processes of hydrodynamics, quark\ncoalescence, and jet fragmentation, illustrates their importance over a wide\n$p_{\\rm T}$ range.", + "category": "nucl-ex" + }, + { + "text": "Quasifree Lambda, Sigma^0, and Sigma^- electroproduction from 1,2H,\n 3,4He, and carbon: Kaon electroproduction from light nuclei and hydrogen, using 1H, 2H, 3He,\n4He, and Carbon targets has been measured at Jefferson Laboratory. The\nquasifree angular distributions of Lambda and Sigma hyperons were determined at\nQ^2= 0.35(GeV/c)^2 and W= 1.91GeV. Electroproduction on hydrogen was measured\nat the same kinematics for reference.", + "category": "nucl-ex" + }, + { + "text": "The KDK (potassium decay) experiment: Potassium-40 (${}^{40}$K) is a background in many rare-event searches and may\nwell play a role in interpreting results from the DAMA dark-matter search. The\nelectron-capture decay of ${}^{40}$K to the ground state of ${}^{40}$Ar has\nnever been measured and contributes an unknown amount of background. The KDK\n(potassium decay) collaboration will measure this branching ratio using a\n${}^{40}$K source, an X-ray detector, and the Modular Total Absorption\nSpectrometer at Oak Ridge National Laboratory.", + "category": "nucl-ex" + }, + { + "text": "Search for Pentaquark Theta+ in Hadronic Reaction at J-PARC: A variety of nuclear and hadron physics experiments are being performed using\nmeson beams at the J-PARC Hadron Facility. As the first experiment at the\nfacility, the pentaquark Theta+ was searched for in the pi- p -> K- X reaction\nwith a missing-mass resolution of 2 MeV (FWHM). The number of accumulated beam\npions are 7.8x10^10 and 8.1x10^10 for different beam momenta of 1.92 and 2.01\nGeV/c, respectively. No significant structure was observed in the missing mass\nspectra. Upper limits of the production cross section are obtained to be\n0.28ub/sr in the laboratory frame at 90% confidence level for each beam\nmomenta. With a help of theoretical models, an upper limit of the total decay\nwidth of Theta+ was estimated to be 0.36 and 1.9 MeV for J^P = 1/2+ and 1/2-\nstates, respectively.", + "category": "nucl-ex" + }, + { + "text": "Measurement of helium-3 and deuterium stopping power ratio for negative\n muons: The measurement method and results measuring of the stopping power ratio of\nhelium-3 and deuterium atoms for muons slowed down in the D/$^3$He mixture are\npresented. Measurements were performed at four values of pure $^3$He gas target\ndensities, $\\phi_{He} = 0.0337, 0.0355, 0.0359, 0.0363$ (normalized to the\nliquid hydrogen density) and at a density 0.0585 of the D/$^3$He mixture. The\nexperiment was carried out at PSI muon beam $\\mu$E4 with the momentum P$\\mu\n=34.0$ MeV/c. The measured value of the mean stopping ratio $S_{^3He/D}$ is\n$1.66\\pm 0.04$. This value can also be interpreted as the value of mean reduced\nratio of probabilities for muon capture by helium-3 and deuterium atoms.", + "category": "nucl-ex" + }, + { + "text": "Reexamination of $^{6}$Li scattering as a Probe to Investigate the\n Isoscalar Giant Resonances in Nuclei: Inelastic ${}^{6}$Li scattering at 100 MeV/u on ${}^{12}$C and ${}^{93}$Nb\nhave been measured with the high-resolution magnetic spectrometer Grand Raiden.\nThe magnetic-rigidity settings of the spectrometer covered excitation energies\nfrom 10 to 40 MeV and scattering angles in the range $0^\\circ <\n\\theta_{\\text{lab.}}< 2^\\circ$. The isoscalar giant monopole resonance was\nselectively excited in the present data. Measurements free of instrumental\nbackground and the very favorable resonance-to-continuum ratio of ${}^{6}$Li\nscattering allowed for precise determination of the $E0$ strengths in\n${}^{12}$C and ${}^{93}$Nb. It was found that the monopole strength in\n${}^{12}$C exhausts $52 \\pm 3^\\text{(stat.)} \\pm 8 ^\\text{(sys.)}$\\% of the\nenergy-weighted sum rule (EWSR), which is considerably higher than results from\nprevious $\\alpha$-scattering experiments. The monopole strength in ${}^{93}$Nb\nexhausts $92 \\pm 4^\\text{(stat.)} \\pm 10 ^\\text{(sys.)}$\\% of the EWSR, and it\nis consistent with measurements of nuclei with mass number of $A\\approx90$.\nSuch comparison indicates that the isoscalar giant monopole resonance\ndistributions in these nuclei are very similar, and no influence due to nuclear\nstructure was observed.", + "category": "nucl-ex" + }, + { + "text": "\"QM19 summary talk\": Outlook and future of heavy-ion collisions: A summary of the QM19 conference is given by highlighting a few selected\nresults. These are discussed as examples to illustrate the exciting future of\nheavy-ion collisions and the need for further instrumentation. (The arXiv\nversion is significantly longer than the printed proceedings, with more\nfigures.)", + "category": "nucl-ex" + }, + { + "text": "Highlights of Crystal Ball Physics: Differential and total cross sections are presented for pi- - and K- -induced\nreactions on a proton target leading to all-neutral final states. Also shown\nare rates for rare and upper limits for forbidden eta-meson decays to test\nChiral Perturbation Theory, the pi0-pi0 interactions and C and CP invariance.", + "category": "nucl-ex" + }, + { + "text": "Moments of Spin Structure Functions: Sum Rules and Polarizabilities: Nucleon structure study is one of the most important research areas in modern\nphysics and has challenged us for decades. Spin has played an essential role\nand often brought surprises and puzzles to the investigation of the nucleon\nstructure and the strong interaction. New experimental data on nucleon spin\nstructure at low to intermediate momentum transfers combined with existing high\nmomentum transfer data offer a comprehensive picture in the strong region of\nthe interaction and of the transition region from the strong to the\nasymptotic-free region. Insight for some aspects of the theory for the strong\ninteraction, Quantum Chromodynamics (QCD), is gained by exploring lower moments\nof spin structure functions and their corresponding sum rules. These moments\nare expressed in terms of an operator-product expansion using quark and gluon\ndegrees of freedom at moderately large momentum transfers. The higher-twist\ncontributions have been examined through the evolution of these moments as the\nmomentum transfer varies from higher to lower values. Furthermore, QCD-inspired\nlow-energy effective theories, which explicitly include chiral symmetry\nbreaking, are tested at low momentum transfers. The validity of these theories\nis further examined as the momentum transfer increases to moderate values. It\nis found that chiral perturbation theory calculations agree reasonably well\nwith the first moment of the spin structure function g_1 at low momentum\ntransfer of 0.05 - 0.1 GeV^2 but fail to reproduce some of the higher moments,\nnoticeably, the neutron data in the case of the generalized polarizability\nDelta_LT. The Burkhardt-Cottingham sum rule has been verified with good\naccuracy in a wide range of Q^2 assuming that no singular behavior of the\nstructure functions is present at very high excitation energies.", + "category": "nucl-ex" + }, + { + "text": "The PHOBOS Glauber Monte Carlo: ``Glauber'' models are used to calculate geometric quantities in the initial\nstate of heavy ion collisions, such as impact parameter, number of\nparticipating nucleons and initial eccentricity. The four RHIC experiments have\ndifferent methods for Glauber Model calculations, leading to similar results\nfor various geometric observables. In this document, we describe an\nimplementation of the Monte Carlo based Glauber Model calculation used by the\nPHOBOS experiment. The assumptions that go in the calculation are described. A\nuser's guide is provided for running various calculations.", + "category": "nucl-ex" + }, + { + "text": "Towards the Quark Gluon Plasma: We discuss recent experimental results in the field of ultra-relativistic\nnuclear collisions. The emerging ``picture'' is a collectively expanding,\ninitially hot and dense fireball in which strangeness- and low-mass di-lepton\npair production are enhanced and J/$\\Psi$ production is suppressed compared to\nexpectations from nucleon-nucleon collisions. It is argued that, taken\ntogether, these data provide circumstantial evidence that a (at least partly)\npartonic phase was produced in such collisions.", + "category": "nucl-ex" + }, + { + "text": "Searching for three-nucleon short-range correlations: Electron scattering measurements from high-momentum nucleons in nuclei at\nSLAC and Jefferson Lab (JLab) have shown that these nucleons are generally\nassociated with two-nucleon short-range correlations (2N-SRCs). These SRCs are\nformed when two nucleons in the nucleus interact at short distance via the\nstrong tensor attraction or repulsive core of the NN potential. A series of\nmeasurements at JLab have mapped out the A dependence and isospin dependence of\n2N-SRCs, and have begun to map out their momentum structure. However, we do not\nyet know if 3N-SRCs, similar high-momentum configurations of three nucleons,\nplay an important role in nuclei. We summarize here previous attempts to\nisolate 3N-SRCs, go over the limitations of these previous attempts, and\ndiscuss the present and near-term prospects for searching for 3N-SRCs, mapping\nout their A dependence in nuclei, and constraining their isospin and momentum\nstructure.", + "category": "nucl-ex" + }, + { + "text": "A new method for the experimental study of topological effects in the\n quark-gluon plasma: A new method is presented for the quantitative measurement of charge\nseparation about the reaction plane. A correlation function is obtained whose\nshape is concave when there is a net separation of positive and negative\ncharges. Correlations not specifically associated with charge, from flow, jets\nand momentum conservation, do not influence the shape or magnitude of the\ncorrelation function. Detailed simulations are used to demonstrate the\neffectiveness of the method for the quantitative measurement of charge\nseparation. Such measurements are a pre-requisite to the investigation of\ntopological charge effects in the QGP as derived from the \"strong $\\cal{CP}$\nproblem\".", + "category": "nucl-ex" + }, + { + "text": "Nuclear track emulsion in search for the Hoyle-state in dissociation of\n relativistic ${}^{12}$C nuclei: Production of ensembles of $\\alpha$-particle triples associated with the\nHoyle state (the second excited state of the ${}^{12}$C nucleus) in peripheral\ndissociation of relativistic ${}^{12}$C nuclei is studied. Stacks of nuclear\ntrack emulsion pellicles exposed to ${}^{12}$C with an energy from hundreds MeV\nto a few GeV per nucleon serve as the material for studies. The Hoyle state\ndecays are reconstructed via measurement of emission angles of $\\alpha$\nparticles with the precision sufficient for identification of the unstable\n${}^{8}$Be nucleus. The estimate of the contribution of Hoyle's state to the\n${}^{12}$C $\\to$ 3$\\alpha$ dissociation is 10-15\\%.", + "category": "nucl-ex" + }, + { + "text": "Potential for measurement of the tensor electric and magnetic\n polarizabilities of the deuteron in storage-ring experiments with polarized\n beams: Measurement of the tensor electric and magnetic polarizabilities of the\ndeuteron is of great interest, especially in connection with the possibilities\nof COSY and GSI. These polarizabilities can be measured in storage rings by the\nfrozen spin method providing a disappearance of g-2 precession. This method\nwill be used in the planned deuteron electric-dipole-moment experiment in\nstorage rings. The tensor electric polarizability of the deuteron significantly\ninfluences the buildup of the vertical polarization in the above experiment.\nThe spin interactions depending on the electric dipole moment, the tensor\nelectric polarizability, and main systematical errors caused by field\nmisalignments have very different symmetries. For the considered experimental\nconditions, the sensitivity to the deuteron EDM of $1\\times10^{-29} e\\cdot$cm\ncorresponds to measuring the both of tensor polarizabilities with an accuracy\nof $\\delta\\alpha_T\\approx\\delta\\beta_T\\approx5\\times10^{-42}$ cm$^3$. This\nconservative estimate can be improved by excluding the systematical error\ncaused by the field instability which is negligible for the measurement of the\ntensor polarizabilities. To find the tensor magnetic polarizability, the\nhorizontal components of the polarization vector should be measured.", + "category": "nucl-ex" + }, + { + "text": "Bulk Properties of the System Formed in Au+Au Collisions at\n $\\sqrt{s_{\\mathrm{NN}}}$ = 14.5 GeV: We report systematic measurements of bulk properties of the system created in\nAu+Au collisions at $\\sqrt{s_{\\mathrm{NN}}}$ = 14.5 GeV recorded by the STAR\ndetector at the Relativistic Heavy Ion Collider (RHIC).The transverse momentum\nspectra of $\\pi^{\\pm}$, $K^{\\pm}$ and $p(\\bar{p})$ are studied at mid-rapidity\n($|y| < 0.1$) for nine centrality intervals. The centrality, transverse\nmomentum ($p_T$),and pseudorapidity ($\\eta$) dependence of inclusive charged\nparticle elliptic flow ($v_2$), and rapidity-odd charged particles directed\nflow ($v_{1}$) results near mid-rapidity are also presented. These measurements\nare compared with the published results from Au+Au collisions at other\nenergies, and from Pb+Pb collisions at $\\sqrt{s_{\\mathrm{NN}}}$ = 2.76 TeV. The\nresults at $\\sqrt{s_{\\mathrm{NN}}}$ = 14.5 GeV show similar behavior as\nestablished at other energies and fit well in the energy dependence trend.\nThese results are important as the 14.5 GeV energy fills the gap in $\\mu_B$,\nwhich is of the order of 100 MeV,between $\\sqrt{s_{\\mathrm{NN}}}$ =11.5 and\n19.6 GeV. Comparisons of the data with UrQMD and AMPT models show poor\nagreement in general.", + "category": "nucl-ex" + }, + { + "text": "Optical Alignment System for the PHENIX Muon Tracking Chambers: A micron-precision optical alignment system (OASys) for the PHENIX muon\ntracking chambers is developed. To ensure the required mass resolution of\nvector meson detection, the relative alignment between three tracking station\nchambers must be monitored with a precision of 25$\\mu$m. The OASys is a\nstraightness monitoring system comprised of a light source, lens and CCD\ncamera, used for determining the initial placement as well as for monitoring\nthe time dependent movement of the chambers on a micron scale.", + "category": "nucl-ex" + }, + { + "text": "Reactions of a Be-10 beam on proton and deuteron targets: The extraction of detailed nuclear structure information from transfer\nreactions requires reliable, well-normalized data as well as optical potentials\nand a theoretical framework demonstrated to work well in the relevant mass and\nbeam energy ranges. It is rare that the theoretical ingredients can be tested\nwell for exotic nuclei owing to the paucity of data. The halo nucleus Be-11 has\nbeen examined through the 10Be(d,p) reaction in inverse kinematics at\nequivalent deuteron energies of 12,15,18, and 21.4 MeV. Elastic scattering of\nBe-10 on protons was used to select optical potentials for the analysis of the\ntransfer data. Additionally, data from the elastic and inelastic scattering of\nBe-10 on deuterons was used to fit optical potentials at the four measured\nenergies. Transfers to the two bound states and the first resonance in Be-11\nwere analyzed using the Finite Range ADiabatic Wave Approximation (FR-ADWA).\nConsistent values of the spectroscopic factor of both the ground and first\nexcited states were extracted from the four measurements, with average values\nof 0.71(5) and 0.62(4) respectively. The calculations for transfer to the first\nresonance were found to be sensitive to the size of the energy bin used and\ntherefore could not be used to extract a spectroscopic factor.", + "category": "nucl-ex" + }, + { + "text": "Mid-rapidity anti-baryon to baryon ratios in pp collisions at $\\sqrt{s}$\n = 0.9, 2.76 and 7 TeV measured by ALICE: The ratios of yields of anti-baryons to baryons probes the mechanisms of\nbaryon-number transport. Results for $\\bar{\\rm p}/{\\rm p}$, $\\bar{\\rm\n\\Lambda}/{\\rm \\Lambda}$, $\\rm\\bar{\\Xi}$$^{+}/{\\rm \\Xi}^{-}$ and\n$\\rm\\bar{\\Omega}$$^{+}/{\\rm \\Omega}^{-}$ in pp collisions at $\\sqrt{s} = 0.9$,\n2.76 and 7 TeV, measured with the ALICE detector at the LHC, are reported.\nWithin the experimental uncertainties and ranges covered by our measurement,\nthese ratios are independent of rapidity, transverse momentum and multiplicity\nfor all measured energies. The results are compared to expectations from event\ngenerators, such as PYTHIA and HIJING-B, that are used to model the particle\nproduction in pp collisions. The energy dependence of $\\bar{\\rm p}/{\\rm p}$,\n$\\bar{\\rm \\Lambda}/{\\rm \\Lambda}$, $\\rm\\bar{\\Xi}$$^{+}/{\\rm \\Xi^{-}}$ and\n$\\rm\\bar{\\Omega}$$^{+}/{\\rm \\Omega^{-}}$, reaching values compatible with unity\nfor $\\sqrt{s} = 7$ TeV, complement the earlier $\\bar{\\rm p}/{\\rm p}$\nmeasurement of ALICE. These dependencies can be described by exchanges with the\nRegge-trajectory intercept of $\\alpha_{\\rm {J}} \\approx 0.5$, which are\nsuppressed with increasing rapidity interval ${\\rm \\Delta} y$. Any significant\ncontribution of an exchange not suppressed at large ${\\rm \\Delta} y$ (reached\nat LHC energies) is disfavoured.", + "category": "nucl-ex" + }, + { + "text": "Positrons at JLab - Advancing Nuclear Science in Hall B: In this talk I address two high impact physics programs that require the use\nof polarized and unpolarized positron beams in addition to using electron beams\nof the same energy. First, I address what will be gained from using positron\nbeams in addition to electron beams in the extraction of the Compton Form\nFactors (CFFs) and generalized parton distributions (GPDs) from Deeply Virtual\nCompton Scattering (DVCS) on a proton target. As a second high impact science\nprogram I discuss an experimental scenario using unpolarized positrons to\nmeasure elastic scattering on protons in an effort to determine definitively\nthe 2-photon exchange contributions in order to resolve a longstanding\ndiscrepancy in the determination of the proton's electric and magnetic form\nfactors.", + "category": "nucl-ex" + }, + { + "text": "On the Microscopic Level Density Models for Nuclei Near Z=28 Shell\n Closure: A comprehensive test of level density models for explaining the decay of\nexcited compound nuclei, 54 Mn, 56 Fe, 58 Co, 60 Ni, 61 Ni and 63 Cu, in the\nenergy range of 28 - 36 MeV has been performed. The compound nuclei of interest\nin the desired ranges are populated using 6 Li based transfer reactions. The\nproton decay spectrum for each excitation energy bins has been measured. The\nmeasured proton spectrum has been reproduced using statistical model\ncalculations with different level density models. A variance minimised approach\nhas been employed for analysing the prediction capability of different level\ndensity models. This approach has been converged to Gogny\nHartree-Fock-Bogoliubov(HFB) microscopic level density model and which is\nattributed as the most accurate model for the desired nuclei.", + "category": "nucl-ex" + }, + { + "text": "J/$\u03c8$ and $\u03c8$(2S) Production in Small Systems with PHENIX: The suppression of the $\\psi$(2S) nuclear modification factor has been seen\nas a trademark signature of final state effects in large collision systems for\ndecades. In small systems, deviations of the nuclear modification from unity\nhad been attributed to cold nuclear matter effects until the observation of\nstrong differential suppression of the $\\psi$(2S) state in $p/d+$A collisions,\nwhich suggests the presence of final state effects. In this paper, we present\nresults of J/$\\psi$ and $\\psi$(2S) measurements in the dimuon decay channel for\n$p+p$, $p+$Al, and $p+$Au collision systems at $\\sqrt{s_{_{NN}}}$ = 200 GeV.\nKey results include the nuclear modification factors $R_{pA}$ as a function of\ncentrality and rapidity. The measurements are compared with shadowing and\ntransport model predictions, as well as to complementary measurements at LHC\nenergies.", + "category": "nucl-ex" + }, + { + "text": "Elliptic flow of charged pions, protons and strange particles emitted in\n Pb+Au collisions at top SPS energy: Differential elliptic flow spectra v2(pT) of \\pi-, K0short, p, \\Lambda have\nbeen measured at \\sqrt(s NN)= 17.3 GeV around midrapidity by the\nCERN-CERES/NA45 experiment in mid-central Pb+Au collisions (10% of\n\\sigma(geo)). The pT range extends from about 0.1 GeV/c (0.55 GeV/c for\n\\Lambda) to more than 2 GeV/c. Protons below 0.4 GeV/c are directly identified\nby dE/dx. At higher pT, proton elliptic flow v2(pT) is derived as a\nconstituent, besides \\pi+ and K+, of the elliptic flow of positive pion\ncandidates. The retrieval requires additional inputs: (i) of the particle\ncomposition, and (ii) of v2(pT) of positive pions. For (i), particle ratios\nobtained by NA49 were adapted to CERES conditions; for (ii), the measured\nv2(pT) of negative pions is substituted, assuming \\pi+ and \\pi- elliptic flow\nmagnitudes to be sufficiently close. The v2(pT) spectra are compared to\nideal-hydrodynamics calculations. In synopsis of the series \\pi- - K0short - p\n- \\Lambda, flow magnitudes are seen to fall with decreasing pT progressively\neven below hydro calculations with early kinetic freeze-out (Tf= 160 MeV)\nleaving not much time for hadronic evolution. The proton v2(pT) data show a\ndownward swing towards low pT with excursions into negative v2 values. The\npion-flow isospin asymmetry observed recently by STAR at RHIC, invalidating in\nprinciple our working assumption, is found in its impact on proton flow\nbracketed from above by the direct proton flow data, and not to alter any of\nour conclusions. Results are discussed in perspective of recent viscous\ndynamics studies which focus on late hadronic stages.", + "category": "nucl-ex" + }, + { + "text": "Energy scan of correlations in p+p and Be+Be from NA61/SHINE: The existence of the critical point (CP) of strongly interacting matter is\nstill an open problem. An extensive strong interactions program including a\nsearch of the CP and the study of the onset of deconfinement was started by the\nNA61/SHINE experiment at the CERN SPS. A two dimensional scan of the phase\ndiagram scan is performed to search for the CP and to shed light on the phase\ntransition region. This program includes studies of hadron production in\nproton-proton, proton-nucleus and nucleus-nucleus interactions measured in a\nwide range of colliding energy and system size. Correlations between various\nobservables measured at midrapidity as well as in separated rapidity intervals\nare considered as additional and sensitive tools of this phase diagram scan. We\npresent NA61/SHINE results of studies of energy dependence of two-particle\ncorrelations of pseudo-rapidity and azimuthal angle in p+p collisions at the\nSPS and the first results on correlations between multiplicity and mean\ntransverse momentum in 7Be+9Be collisions at 150A GeV/c obtained for separated\npseudo-rapidity intervals (so called long-range correlations). Comparison with\ndata calculations using the EPOS 1.99 model are also discussed.", + "category": "nucl-ex" + }, + { + "text": "Measuring the lepton sign asymmetry in elastic electron-proton\n scattering with OLYMPUS: OLYMPUS is a particle physics experiment that collected data in 2012 at DESY,\nin Hamburg, Germany, on the asymmetry between positron-proton and\nelectron-proton elastic scattering cross sections. A non-zero asymmetry is\nevidence of hard two-photon exchange, which has been hypothesized to cause the\ndiscrepancy in measurements of the proton's electromagnetic form factors.\nAlternating electron and positron beams, accelerated to 2 GeV, were directed\nthrough a windowless, gaseous, hydrogen target, and the scattered lepton and\nrecoiling proton were detected in coincidence using a large acceptance magnetic\nspectrometer. Determining the relative integrated luminosity between the\nelectron and positron data sets was critical, and a new technique, involving\nmulti-interaction events, was developed to achieve the desired sub-percent\naccuracy. A detailed Monte Carlo simulation was built in order to reproduce the\nconvolution of systematic effects at every stage of the experiment. The first\nstage in the simulation was new radiative event generator, which permitted the\nfull simulation of the non-trivial, radiative corrections to the measurement.\nThe analysis of the data and simulation showed that the lepton sign asymmetry\nrises by several percent between a momentum transfer of 0.5 GeV$^2/c^2$ and\n2.25 GeV$^2/c^2$. This rise as a function of increasing momentum transfer\nconfirms that two photon exchange at least partially contributes to the proton\nform factor discrepancy.", + "category": "nucl-ex" + }, + { + "text": "Single- and Double-Pion Production in Nucleon Collisions on the Nucleon\n and on Nuclei -- the ABC Effect and its Possible Origin in a Dibaryonic\n Resonance: The ABC effect -- an intriguing low-mass enhancement in the $\\pi\\pi$\ninvariant mass spectrum -- is known from inclusive measurements of two-pion\nproduction in nuclear fusion reactions. First exclusive measurements carried\nout at CELSIUS-WASA for the fusion reactions leading to d or $^3$He reveal this\neffect to be a $\\sigma$ channel phenomenon associated with the formation of a\n$\\Delta\\Delta$ system in the intermediate state and combined with a\nresonance-like behavior in the total cross section. Together with the\nobservation that the differential distributions do not change in shape over the\nresonance region the features fulfill the criteria of an isoscalar s-channel\nresonance in $pn$ and $NN\\pi\\pi$ systems, if the two emitted nucleons are\nbound. It obviously is robust enough to survive in nuclei as a dibaryonic\nresonance configuration. In this context also the phenomenon of $N\\Delta$\nresonances is reexamined.", + "category": "nucl-ex" + }, + { + "text": "Using Nab to determine correlations in unpolarized neutron decay: The Nab experiment will measure the ratio of the weak axial-vector and vector\ncoupling constants $\\lambda=g_A/g_V$ with precision\n$\\delta\\lambda/\\lambda\\sim3\\times10^{-4}$ and search for a Fierz term $b_F$ at\na level $\\Delta b_F<10^{-3}$. The Nab detection system uses thick, large area,\nsegmented silicon detectors to very precisely determine the decay proton's time\nof flight and the decay electron's energy in coincidence and reconstruct the\ncorrelation between the antineutrino and electron momenta. Excellent\nunderstanding of systematic effects affecting timing and energy reconstruction\nusing this detection system are required. To explore these effects, a series of\nex situ studies have been undertaken, including a search for a Fierz term at a\nless sensitive level of $\\Delta b_F<10^{-2}$ in the beta decay of $^{45}$Ca\nusing the UCNA spectrometer.", + "category": "nucl-ex" + }, + { + "text": "Dual Magnetic Separator for TRI$\u03bc$P: The TRI$\\mu$P facility, under construction at KVI, requires the production\nand separation of short-lived and rare isotopes. Direct reactions,\nfragmentation and fusion-evaporation reactions in normal and inverse kinematics\nare foreseen to produce nuclides of interest with a variety of heavy-ion beams\nfrom the superconducting cyclotron AGOR. For this purpose, we have designed,\nconstructed and commissioned a versatile magnetic separator that allows\nefficient injection into an ion catcher, i.e., gas-filled stopper/cooler or\nthermal ionizer, from which a low energy radioactive beam will be extracted.\nThe separator performance was tested with the production and clean separation\nof $^{21}$Na ions, where a beam purity of 99.5% could be achieved. For\nfusion-evaporation products, some of the features of its operation as a\ngas-filled recoil separator were tested.", + "category": "nucl-ex" + }, + { + "text": "Photoneutron emission cross sections for $^{13}$C: Photoneutron emission cross sections were measured for $^{13}$C below $2n$\nthreshold using quasi-monochromatic $\\gamma$-ray beams produced in laser\nCompton-scattering at the NewSUBARU synchrotron radiation facility. The data\nshow fine structures in the low-energy tail of the giant-dipole resonance; the\nintegrated strength of the fine structure below 18~MeV is intermediate among\nthe past measurements with bremsstrahlung and the positron annihilation\n$\\gamma$ rays. We compare the photoneutron emission data with the {\\sf TALYS}\nstatistical model calculation implemented with the simple modified Lorentzian\nmodel of $E1$ and $M1$ strengths. We also compare the total photoabsorption\ncross sections for $^{13}$C with the shell model and antisymmetrized molecular\ndynamics calculations as well as the statistical model calculation. We further\ninvestigate the consistency between the present photoneutron emission and the\nreverse $^{12}$C(n,$\\gamma$) cross sections through their corresponding\nastrophysical rate.", + "category": "nucl-ex" + }, + { + "text": "Statistical analysis of experimental multifragmentation events in\n $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon: A statistical multifragmentation model (SMM) is applied to the experimentally\nobserved multifragmentation events in an intermediate heavy ion reaction.Using\nthe temperature and symmetry energy extracted from the isobaric yield ratio\n(IYR) method based on the Modified Fisher Model (MFM), SMM is applied to the\nreaction $^{64}$Zn + $^{112}$Sn at 40 MeV/nucleon. The experimental isotope\ndistribution and mass distribution of the primary reconstructed fragments are\ncompared without afterburner and they are well reproduced. The extracted\ntemperature $T$ and symmetry energy coefficient $a_{sym}$ from SMM simulated\nevents, using the IYR method, are also consistent with those from the\nexperiment. These results strongly suggest that in the multifragmentation\nprocess there is a freezeout volume, in which the thermal and chemical\nequilibrium is established before or at the time of the intermediate-mass\nfragments emission.", + "category": "nucl-ex" + }, + { + "text": "Electroexcitation of the Roper resonance for 1.7 < Q2 < 4.5 GeV2 in ep\n -> enpi+: The helicity amplitudes of the electroexcitation of the Roper resonance are\nextracted for 1.7 < Q2 < 4.5 GeV2 from recent high precision JLab-CLAS cross\nsection and longitudinally polarized beam asymmetry data for pi+\nelectroproduction on protons at W=1.15-1.69 GeV. The analysis is made using two\napproaches, dispersion relations and a unitary isobar model, which give\nconsistent results. It is found that the transverse helicity amplitude A_{1/2}\nfor the gamma* p -> N(1440)P11 transition, which is large and negative at Q2=0,\nbecomes large and positive at Q2 ~ 2 GeV2, and then drops slowly with Q2. The\nlongitudinal helicity amplitude S_{1/2}, which was previously found from CLAS\nep -> eppi0,enpi+ data to be large and positive at Q2=0.4,0.65 GeV2, drops with\nQ2. Available model predictions for gamma* p -> N(1440)P11 allow us to conclude\nthat these results provide strong evidence in favor of N(1440)P11 as a first\nradial excitation of the 3q ground state. The results of the present paper also\nconfirm the conclusion of our previous analysis for Q2 < 1 GeV2 that the\npresentation of N(1440)P11 as a 3qG hybrid state is ruled out.", + "category": "nucl-ex" + }, + { + "text": "First test of a cryogenic scintillation module with a CaWO4 scintillator\n and a low-temperature photomultiplier down to 6 K: Future cryogenic experiments searching for rare events require reliable,\nefficient and robust techniques for the detection of photons at temperatures\nwell below that to which low-temperature photomultipliers (PMT) were\ncharacterised. Motivated by this we investigated the feasibility of a\nlow-temperature PMT for the detection of scintillation from crystalline\nscintillators at T = 6 K. The scintillation module was composed of a CaWO4\nscintillator and a low-temperature PMT D745B from ET Enterprises. The PMT\nresponsivity was studied at T=290, 77 and 6 K using gamma-quanta from 241Am (60\nkeV) and 57Co (122 and 136 keV) sources. We have shown that the low-temperature\nPMT retains its single photon counting ability even at cryogenic temperatures.\nAt T = 6 K, the response of the PMT decreases to 51 +- 13 % and 27 +- 6 % when\nassessed in photon counting and pulse height mode, respectively. Due to the\nlight yield increase of the CaWO4 scintillating crystal the overall\nresponsivity of the scintillation modules CaWO4+PMT is 94 +- 15 % (photon\ncounting) and 48 +- 8 % (pulse height) when cooling to T = 6 K. The dark count\nrate was found to be 20 s-1. The energy resolution of the module remains\nsimilar to that measured at room temperature using either detection mode. It is\nconcluded that commercially available low-temperature PMT are well suited for\ndetection of scintillation light at cryogenic temperatures.", + "category": "nucl-ex" + }, + { + "text": "Searching for the critical point of strongly interacting matter in\n nucleus-nucleus collisions at CERN SPS: The search for experimental signatures of the critical point (CP) of strongly\ninteracting matter is one of the main objectives of the NA61/SHINE experiment\nat CERN SPS. In the course of the experiment, a beam momentum and system size\nscan is performed. Local proton density fluctuations in transverse momentum\nspace represent an order parameter of the chiral phase transition and are\nexpected to scale according to a universal power-law in the vicinity of the CP;\nwe probe their behavior through an intermittency analysis of the proton second\nscaled factorial moments (SSFMs) in transverse momentum space. Previous such\nanalyses revealed power-law behavior in NA49 Si+Si collisions at 158$A$\nGeV/$c$, with no intermittency observed in lighter or heavier NA49 & NA61/SHINE\nsystems at the same energy. We now extend the analysis to NA61/SHINE Ar+Sc\ncollisions at 150$A$ GeV/$c$, similar in size and baryochemical potential to\nNA49 Si+Si. We employ statistical techniques to subtract non-critical\nbackground and estimate statistical and systematic uncertainties. Subsequently,\nwe use Monte Carlo simulations to assess the statistical significance of the\nobserved intermittency effect.", + "category": "nucl-ex" + }, + { + "text": "Hard photon and neutral pion production in cold nuclear matter: The production of hard photons and neutral pions in 190 MeV proton induced\nreactions on C, Ca, Ni, and W targets has been for the first time concurrently\nstudied. Angular distributions and energy spectra up to the kinematical limit\nare discussed and the production cross-sections are presented. From the target\nmass dependence of the cross-sections the propagation of pions through nuclear\nmatter is analyzed and the production mechanisms of hard photons and primordial\npions are derived. It is found that the production of subthreshold particles\nproceeds mainly through first chance nucleon-nucleon collisions. For the most\nenergetic particles the mass scaling evidences the effect of multiple\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "Measurements of strange and multi-strange hadrons elliptic flow in\n isobar collisions at RHIC by STAR: We present measurements of elliptic flow ($v_{2}$) of $K_{s}^{0}$, $\\Lambda$,\n$\\bar{\\Lambda}$, $\\phi$, $\\Xi^{-}$, $\\overline{\\Xi}^{+}$, and\n$\\Omega^{-}$+$\\overline{\\Omega}^{+}$ at mid-rapidity ($|\\eta| <$ 1.0) in isobar\ncollisions ($^{96}_{44}$Ru+$^{96}_{44}$Ru and $^{96}_{40}$Zr+$^{96}_{40}$Zr) at\n$\\sqrt{s_{\\mathrm{NN}}}$ = 200 GeV. The centrality and transverse momentum\n($p_{\\mathrm{T}}$) dependence of elliptic flow is presented. The number of\nconstituent quark (NCQ) scaling of $v_{2}$ in isobar collisions is discussed.\n$p_{T}$-integrated elliptic flow ($\\left\\langle v_{2}\\right\\rangle$) is\nobserved to increase from central to peripheral collisions. The ratio of\n$\\left\\langle v_{2}\\right\\rangle$ between the two isobars shows a deviation\nfrom unity for strange hadrons ($K_{s}^{0}$, $\\Lambda$ and $\\bar{\\Lambda}$)\nindicating a difference in nuclear structure and deformation. A system size\ndependence of strange hadron $v_{2}$ at high $p_{T}$ is observed among Ru+Ru,\nZr+Zr, Cu+Cu, Au+Au, and U+U systems. A multi-phase transport (AMPT) model with\nstring melting (SM) describes the experimental data well in the measured\n$p_{\\mathrm{T}}$ range for isobar collisions at $\\sqrt{s_{\\mathrm{NN}}}$ = 200\nGeV.", + "category": "nucl-ex" + }, + { + "text": "Characterization of electroless nickel-phosphorus plating for\n ultracold-neutron storage: Electroless nickel plating is an established industrial process that provides\na robust and relatively low-cost coating suitable for transporting and storing\nultracold neutrons (UCN). Using roughness measurements and UCN-storage\nexperiments we characterized UCN guides made from polished aluminum or\nstainless-steel tubes plated by several vendors. All electroless nickel\nplatings were similarly suited for UCN storage with an average loss probability\nper wall bounce of $2.8\\cdot10^{-4}$ to $4.1\\cdot10^{-4}$ for energies between\n90 neV and 190 neV, or a ratio of imaginary to real Fermi potential $\\eta$ of\n$1.7\\cdot10^{-4}$ to $3.3\\cdot10^{-4}$. Measurements at different elevations\nindicate that the energy dependence of UCN losses is well described by the\nimaginary Fermi potential. Some special considerations are required to avoid an\nincrease in surface roughness during the plating process and hence a reduction\nin UCN transmission. Increased roughness had only a minor impact on storage\nproperties. Based on these findings we chose a vendor to plate the\nUCN-production vessel that will contain the superfluid-helium converter for the\nnew TRIUMF UltraCold Advanced Neutron (TUCAN) source, achieving acceptable\nUCN-storage properties with ${\\eta=3.5(5)\\cdot10^{-4}}$.", + "category": "nucl-ex" + }, + { + "text": "Recent results on Light Flavor from STAR: These proceedings present an overview of the recent results on light flavor\nby the STAR experiment at RHIC.", + "category": "nucl-ex" + }, + { + "text": "Fragment Kinetic Energies and Modes of Fragment Formation: Kinetic energies of light fragments A <= 10 from the decay of target\nspectators in 197Au 197Au collisions at 1000 MeV per nucleon have been measured\nwith high-resolution telescopes at backward angles. Except for protons and\napart from the observed evaporation components, the kinetic-energy spectra\nexhibit slope temperatures of about 17 MeV, independent of the particle\nspecies, but not corresponding to the thermal or chemical degrees of freedom at\nbreakup. It is suggested that these slope temperatures may reflect the\nintrinsic Fermi motion and thus the bulk density of the spectator system at the\ninstant of becoming unstable.\n PACS numbers: 25.70.Pq, 21.65.+f, 25.70.Mn", + "category": "nucl-ex" + }, + { + "text": "A new precision measurement of the \u03b1-decay half-life of 190Pt: A laboratory measurement of the $\\alpha$-decay half-life of $^{190}$Pt has\nbeen performed using a low background Frisch grid ionisation chamber. A total\namount of 216.60(17) mg of natural platinum has been measured for 75.9 days.\nThe resulting half-life is $(4.97\\pm0.16)\\times 10^{11}$ years, with a total\nuncertainty of 3.2%. This number is in good agreement with the half-life\nobtained using the geological comparison method.", + "category": "nucl-ex" + }, + { + "text": "Beam Energy Dependence of Clan Multiplicity at RHIC: In this paper, STAR's measurement of clan multiplicity is presented for AuAu\ncollisions at $\\sqrt{s_\\mathrm{NN}}$ = 7.7, 11.5, 19.6, 27, 39, 62.4 and 200\nGeV, for a variety of centrality classes. The mean number of particles per clan\nis found to decrease with decreasing centrality. Within the same centrality\nclass, the mean number of particles per clan exhibits a reduction between 19.6\nGeV and 62 GeV, with the minimum around 27 GeV. The structure is visible for\nmost centralities, and most prominent for central collisions.", + "category": "nucl-ex" + }, + { + "text": "Simulations of the nEDM@SNS light collection system efficiency: A system for collecting the scintillation light produced by the capture\nprocess of ultra-cold neutrons (UCN) on polarized $^{3}$He is discussed and\nresults from simulations of its performance are presented. This system will be\nimplemented in nEDM@SNS, the experiment searching for the neutron electric\ndipole moment (nEDM) at the Spallation Neutron Source (SNS) at Oak Ridge\nNational Laboratory. Simulation results show that the light collection system\ncollects on average 17 photoelectrons per UCN-$^{3}$He capture event\n(sufficient to generate a robust signal), reconstructs the event location in\nthe beam direction to approximately 3 cm accuracy, detects capture events with\na high and spatially uniform efficiency (0.95 with 1% variation), and rejects\ngreater than 50% of beta decay background events.", + "category": "nucl-ex" + }, + { + "text": "Response of CdWO4 crystal scintillator for few MeV ions and low energy\n electrons: The response of a CdWO4 crystal scintillator to protons, alpha particles, Li,\nC, O and Ti ions with energies in the range 1 - 10 MeV was measured. The\nnon-proportionality of CdWO4 for low energy electrons (4 - 110 keV) was studied\nwith the Compton Coincidence Technique. The energy dependence of the quenching\nfactors for ions and the relative light yield for low energy electrons was\ncalculated using a semi-empirical approach. Pulse-shape discrimination ability\nbetween gamma quanta, protons, alpha particles and ions was investigated.", + "category": "nucl-ex" + }, + { + "text": "Tracing the Evolution of Temperature in Near Fermi Energy Heavy Ion\n Collisions: The kinetic energy variation of emitted light clusters has been employed as a\nclock to explore the time evolution of the temperature for thermalizing\ncomposite systems produced in the reactions of 26A, 35A and 47A MeV $^{64}$Zn\nwith $^{58}$Ni, $^{92}$Mo and $^{197}$Au. For each system investigated, the\ndouble isotope ratio temperature curve exhibits a high maximum apparent\ntemperature, in the range of 10-25 MeV, at high ejectile velocity. These\nmaximum values increase with increasing projectile energy and decrease with\nincreasing target mass. The time at which the maximum in the temperature curve\nis reached ranges from 80 to 130 fm/c after contact. For each different target,\nthe subsequent cooling curves for all three projectile energies are quite\nsimilar. Temperatures comparable to those of limiting temperature systematics\nare reached 30 to 40 fm/c after the times corresponding to the maxima, at a\ntime when AMD-V transport model calculations predict entry into the final\nevaporative or fragmentation stage of de-excitation of the hot composite\nsystems. Evidence for the establishment of thermal and chemical equilibrium is\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Recent Heavy-Flavor results at STAR: We present the recent results on non-photonic electron (NPE) yields from RHIC\nrun8 p+p collisions. The $e/\\pi$ ratio as a function of $p_T$ in run8 with a\nfactor of 10 reduction of the inner detector material at STAR is found to be\nconsistent with those results from run3 taking into account the NPE from charm\nleptonic decay and the difference of photonic electron yield from photon\nconversion in detector material. \\Jpsi spectra in \\pp and \\cucu collisions at\n\\sNN = 200 GeV with high sampled luminosity \\Jpsi spectrum at high-\\pT follows\n$x_T$ scaling, but the scaling is violated at low \\pT. $J/\\psi$-hadron\ncorrelations in \\pp collisions are studied to understand the \\Jpsi production\nmechanism at high $p_T$. We observed an absence of charged hadrons accompanying\n\\Jpsi on the near-side, in contrast to the strong correlation peak in the\ndi-hadron correlations. This constrains the $B$-meson contribution and jet\nfragmentation to inclusive \\Jpsi to be ${}^{<}_{\\sim}17%$. Yields in\nminimum-bias \\cucu collisions are consistent with those in \\pp collisions\nscaled by the underlying binary nucleon-nucleon collisions in the measured \\pT\nrange. Other measurements and future projects related to heavy-flavors are\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "Analysis of various projectile interactions with Nuclear Emulsion\n Detector nuclei at ~ 1 GeV per nucleon using Coulomb modified Glauber model: The total nuclear reaction cross-section is calculated considering with and\nwithout medium effect by employing Coulomb Modified Glauber Model (CMGM) for\ninteractions of projectiles 56^Fe_26, 84^Kr_36, 132^Xe_54, 197^Au_79 and\n238^U_92 with nuclear emulsion detector (NED) nuclei at around 1 GeV per\nnucleon incident kinetic energy. These calculated reaction cross-sections are\ncorrelated with the different target groups of the NED nuclei. The average\nvalue of various parameters are also calculated and compared with the\ncorresponding experimental results. The number of shower particles emitted in\nan interaction is also calculated and showed good agreement with the\nexperimental result. We observed that the total reaction cross-section\nincreases with increasing the target mass number in case of all the considered\nprojectiles. In addition, it shows that the average value of reaction\ncross-section with nuclear medium effect is in good agreement with the\nexperimental results for projectiles 56^Fe, 84^Kr, 132^Xe, although results of\nprojectiles 197^Au and 238^U are not in agreement with the experimental\nobservations. This study sheds some light on the energy dependence of the\nnuclear reaction cross-section.", + "category": "nucl-ex" + }, + { + "text": "Properties of the fast fission and the coincident emissions of light\n charged particles in $^{40}$Ar + $^{197}$Au reactions at 30 MeV/u: The experiment of Ar+Au reactions at 30 MeV/u have been performed using the\nCompact Spectrometer for Heavy IoN Experiments (CSHINE) in phase I. The\nlight-charged particles are measured by the silicon stripe telescopes in\ncoincidence with the fission fragments recorded by the parallel plate avalanche\ncounters. The distribution properties of the azimuth difference $\\Delta \\phi$\nand the time-of-flight difference $\\Delta TOF$ of the fission fragments are\npresented varying the folding angles which represents the linear momentum\ntransfer from the projectile to the reaction system. The relative abundance of\nthe light charged particles in the fission events to the inclusive events is\ncompared as a function of the laboratory angle $\\theta_{\\rm lab}$ ranging from\n$18^\\circ$ to $60^\\circ$ in various folding angle windows. The angular\nevolution of the yield ratios of p/d and t/d in coincidence with fission\nfragments is investigated. In a relative comparison, tritons are more\nabundantly emitted at small angles, while protons are more abundant at large\nangles. The angular evolution of the neutron richness of the light-charged\nparticles is consistent with the results obtained in previous inclusive\nexperiments.", + "category": "nucl-ex" + }, + { + "text": "Multifragmentation at Intermediate Energy: Dynamics or Statistics?: To make a statement about the nature and mechanism of fragmentation, it is\nnecessary to probe directly any competition, or lack thereof, between the\nemission of various particle species as a function of excitation energy. The\ntask is then to find a global observable that best follows the increase in\nexcitation energy or dissipated energy. In the following, we will consider two\ncontradictory claims that have been advanced recently: 1) the claim for a\npredominantly dynamical fragment production mechanism; and 2) the claim for a\ndominant statistical and thermal process. We will present a new analysis in\nterms of Poissonian reducibility and thermal scaling, which addresses some of\nthe criticisms of the binomial analysis.", + "category": "nucl-ex" + }, + { + "text": "Event-plane flow analysis without non-flow effects: The event-plane method, which is widely used to analyze anisotropic flow in\nnucleus-nucleus collisions, is known to be biased by nonflow effects,especially\nat high $p_t$. Various methods (cumulants, Lee-Yang zeroes) have been proposed\nto eliminate nonflow effects, but their implementation is tedious, which has\nlimited their application so far. In this paper, we show that the\nLee-Yang-zeroes method can be recast in a form similar to the standard\nevent-plane analysis. Nonflow correlations are strongly suppressed by using the\ninformation from the length of the flow vector, in addition to the event-plane\nangle. This opens the way to improved analyses of elliptic flow and\nazimuthally-sensitive observables at RHIC and LHC.", + "category": "nucl-ex" + }, + { + "text": "System-size dependence of the viscous attenuation of anisotropic flow in\n p+Pb and Pb+Pb collisions at LHC energies: The elliptic and triangular flow coefficients ($\\mathrm{v_n, \\, n=2,3}$)\nmeasured in Pb+Pb ($\\sqrt{s_{_{\\rm NN}}} = 2.76$ TeV) and p+Pb ($\\sqrt{s_{_{\\rm\nNN}}} = 5.02$ TeV) collisions, are studied as a function of initial-state\neccentricity ($\\varepsilon_n$), and dimensionless size characterized by the\ncube root of the mid-rapidity charged hadron multiplicity density\n$\\mathrm{\\left< N_{ch} \\right>^{1/3}}$. The results indicate that the influence\nof eccentricity ($\\mathrm{v_n} \\propto \\varepsilon_n$) observed for large\n$\\mathrm{\\left< N_{ch} \\right>}$, is superseded by the effects of viscous\nattenuation for small $\\mathrm{\\left< N_{ch} \\right>}$, irrespective of the\ncolliding species. Strikingly similar acoustic scaling patterns of exponential\nviscous modulation, with a damping rate proportional to $\\mathrm{n^2}$ and\ninversely proportional to the dimensionless size, are observed for the\neccentricity-scaled coefficients for the two sets of colliding species. The\nresulting scaling parameters suggest that, contrary to current predilections,\nthe patterns of viscous attenuation, as well as the specific shear viscosity\n$\\left<\\frac{\\eta}{s}(\\text{T})\\right>$ for the matter created in p+Pb and\nPb+Pb collisions, are comparable.", + "category": "nucl-ex" + }, + { + "text": "Dominance of tensor correlations in high-momentum nucleon pairs studied\n by (p,pd) reaction: The isospin character of p-n pairs at large relative momentum has been\nobserved for the first time in the 16O ground state. A strong population of the\nJ,T=1,0 state and a very weak population of the J,T=0,1 state were observed in\nneutron pick up domain of 16O(p,pd) at 392 MeV. This strong isospin dependence\nat large momentum transfer is not reproduced by the distorted-wave impulse\napproximation calculations with known spectroscopic amplitudes. The results\nindicate the presence of high-momentum protons and neutrons induced by the\ntensor interactions in ground state of 16O.", + "category": "nucl-ex" + }, + { + "text": "Solid State Systems for Electron Electric Dipole Moment and other\n Fundamental Measurements: In 1968, F.L. Shapiro published the suggestion that one could search for an\nelectron EDM by applying a strong electric field to a substance that has an\nunpaired electron spin; at low temperature, the EDM interaction would lead to a\nnet sample magnetization that can be detected with a SQUID magnetometer. One\nexperimental EDM search based on this technique was published, and for a number\nof reasons including high sample conductivity, high operating temperature, and\nlimited SQUID technology, the result was not particularly sensitive compared to\nother experiments in the late 1970's.\n Advances in SQUID and conventional magnetometery had led us to reconsider\nthis type of experiment, which can be extended to searches and tests other than\nEDMs (e.g., test of Lorentz invariance). In addition, the complementary\nmeasurement of an EDM-induced sample electric polarization due to application\nof a magnetic field to a paramagnetic sample might be effective using modern\nultrasensitive charge measurement techniques. A possible paramagnetic material\nis Gd-substituted YIG which has very low conductivity and a net enhancement\n(atomic enhancement times crystal screening) of order unity. Use of a\nreasonable volume (100's of cc) sample of this material at 50 mK and 10 kV/cm\nmight yield an electron EDM sensitivity of $10^{-33}$ e cm or better, a factor\nof $10^6$ improvement over current experimental limits.", + "category": "nucl-ex" + }, + { + "text": "Multiplicity Fluctuations in Au+Au Collisions at RHIC: In the PHOBOS experiment, charged particles are measured in almost the full\nsolid angle. This enables the study of fluctuations and correlations in the\nparticle production over a very wide kinematic range. In this paper, we show\nresults of a direct search for fluctuations identified by an unusual shape of\nthe pseudorapidity distribution. In addition, we use analysis of correlations\nof the multiplicity in similar pseudorapidity bins, placed symmetrically in the\nforward and backward hemispheres, to test the hypothesis of production of\nparticles in clusters.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the Target-Normal Single-Spin Asymmetry in Quasi-Elastic\n Scattering from the Reaction $^3$He$^\\uparrow(e,e^\\prime)$: We report the first measurement of the target single-spin asymmetry, $A_y$,\nin quasi-elastic scattering from the inclusive reaction\n$^3$He$^{\\uparrow}(e,e^\\prime)$ on a $^3$He gas target polarized normal to the\nlepton scattering plane. Assuming time-reversal invariance, this asymmetry is\nstrictly zero for one-photon exchange. A non-zero $A_y$ can arise from the\ninterference between the one- and two-photon exchange processes which is\nsensitive to the details of the sub-structure of the nucleon. An experiment\nrecently completed at Jefferson Lab yielded asymmetries with high statistical\nprecision at $Q^{2}=$ 0.13, 0.46 and 0.97 GeV$^{2}$. These measurements\ndemonstrate, for the first time, that the $^3$He asymmetry is clearly non-zero\nand negative with a statistical significance of (8-10)$\\sigma$. Using measured\nproton-to-$^{3}$He cross-section ratios and the effective polarization\napproximation, neutron asymmetries of $-$(1-3)% were obtained. The neutron\nasymmetry at high $Q^2$ is related to moments of the Generalized Parton\nDistributions (GPDs). Our measured neutron asymmetry at $Q^2=0.97$ GeV$^2$\nagrees well with a prediction based on two-photon exchange using a GPD model\nand thus provides a new, independent constraint on these distributions.", + "category": "nucl-ex" + }, + { + "text": "Structure in the Event-by-Event Energy-Dependent Neutron-Gamma\n Multiplicity Correlations in $^{252}\\text{Cf}$(sf): The emission of neutrons and gamma rays by fission fragments reveal important\ninformation about the properties of fragments immediately following scission.\nThe initial fragment properties, correlations between fragments, and emission\ncompetition give rise to correlations in neutron-gamma emission. Neutron-gamma\ncorrelations are important in nonproliferation applications because the\ncharacterization of fissionable samples relies on the identification of\nsignatures in the measured radiation. Furthermore, recent theoretical and\nexperimental advances have proposed to explain the mechanism of angular\nmomentum generation in fission. In this paper, we present a novel analysis\nmethod of neutrons and gamma rays emitted by fission fragments that allows us\nto discern structure in the observed correlations. We have analyzed data\ncollected on \\ce{^{252}Cf}(sf) at the Chi-Nu array at the Los Alamos Neutron\nScience Center. Through our analysis of the energy-differential neutron-gamma\nmultiplicity covariance, we have observed enhanced neutron-gamma correlations,\ncorresponding to rotational band gamma-ray transitions, at gamma-ray energies\nof $0.7$ and $1.2$ MeV. To shed light on the origin of this structure, we\ncompare the experimental data with the predictions of three model calculations.\nThe origin of the observed correlation structure is understood in terms of a\npositive spin-energy correlation in the generation of angular momentum in\nfission.", + "category": "nucl-ex" + }, + { + "text": "Q_EC values of the Superallowed beta Emitters 50Mn and 54Co: Using a new fast cleaning procedure to prepare isomerically pure ion samples,\nwe have measured the beta-decay Q_EC values of the superallowed beta-emitters\n50Mn and 54Co to be 7634.48(7) keV and 8244.54(10) keV, respectively, results\nwhich differ significantly from the previously accepted values. The corrected\nFt values derived from our results strongly support new\nisospin-symmetry-breaking corrections that lead to a higher value of the\nup-down quark mixing element, Vud, and improved confirmation of the unitarity\nof the Cabibbo-Kobayashi-Maskawa matrix.", + "category": "nucl-ex" + }, + { + "text": "Leading Modes of the 3pi0 production in proton-proton collisions at\n incident proton momentum 3.35GeV/c: This work deals with the prompt pp-->pp3pi0 reaction where the 3pi0 do not\norigin from the decay of narrow resonances like \\eta(547), \\omega(782),\n\\eta'(958). The reaction was measured for the proton beam momentum of 3.35GeV/c\nwith the WASA-at-COSY detector setup. The dynamics of the reaction is\ninvestigated by Dalitz and Nyborg plots studies. The reaction is described by\nthe model assuming simultaneous excitation of two baryon resonances\n\\Delta(1232) and N*(1440) where resonances are identified by their unique\ndecays topology on the missing mass of two protons MMpp dependent Dalitz and\nNyborg plots. The ratio\nR=\\Gamma(N*(1440)->N\\pi\\pi)/\\Gamma(N*(1440)->\\Delta(1232)\\pi->N\\pi\\pi)= 0.039\n+- 0.011(stat.) +- 0.008(sys.) is measured for the first time in a direct way.\nIt shows that the {N*(1440)->\\Delta(1232)\\pi->N\\pi\\pi} decay is a leading mode\nof 3pi0 production. It is also shown that the MMpp is very sensitive to the\nstructure of the spectral line shape of the N*(1440) resonance as well as on\nthe interaction between the \\Delta(1232) and N*(1440) resonances. The multipion\nspectroscopy - a precision tool to directly access the properties of baryon\nresonances is considered.\n The pp-->pp\\eta(3pi0) reaction was also measured simultaneously. It is shown\nthat the {\\eta} production mechanism via N*(1535) is 43.4 +- 0.8(stat.) +-\n2.0(sys.) of the total production, for the {\\eta} momentum in the CM system\nq_\\eta^CM=0.45-0.7GeV/c. First time momentum dependence of the {\\eta} angular\ndistribution is seen, the strongest effect is observed for the\ncos(\\theta_\\eta^CM) distribution.", + "category": "nucl-ex" + }, + { + "text": "Photon production from gluon mediated quark-anti-quark annihilation at\n confinement: Heavy ion collisions at RHIC produce direct photons at low transverse\nmomentum, $p_{T}$ from 1-3 GeV/c, in excess of the $p$$+$$p$ spectra scaled by\nthe nuclear overlap factor, $T_{AA}$. These low $p_{T}$ photons have a large\nazimuthal anisotropy, $v_{2}$. Theoretical models, including hydrodynamic\nmodels, struggle to quantitatively reproduce the large low $p_{T}$ direct\nphoton excess and $v_{2}$ in a self-consistent manner. This paper presents a\ndescription of the low $p_{T}$ photon flow as the result of increased photon\nproduction from soft-gluon mediated $q$-$\\bar{q}$ interactions as the system\nbecomes color-neutral. This production mechanism will generate photons that\nfollow constituent quark number, $n_{q}$, scaling of $v_{2}$ with an $n_{q}$\nvalue of two for direct photons. $\\chi^{2}$ comparisons of the published PHENIX\ndirect photon and identified particle $v_{2}$ measurements finds that\n$n_{q}$-scaling applied to the direct photon $v_{2}$ data prefers the value\n$n_{q}=1.8$ and agrees with $n_{q}=2$ within errors in most cases. The 0-20%\nand 20-40% Au$+$Au direct photon data are compared to a coalescence-like Monte\nCarlo simulation that calculates the direct photon $v_{2}$ while describing the\nshape of the direct photon $p_{T}$ spectra in a consistent manner. The\nsimulation, while systematically low compared to the data, is in agreement with\nthe Au$+$Au measurement at $p_{T}<3$ GeV/c in both centrality bins.\nFurthermore, this model predicts that higher order flow harmonics, $v_{n}$, in\ndirect photons will follow the modified $n_{q}$-scaling laws seen in identified\nhadron $v_{n}$ with an $n_{q}$ value of two.", + "category": "nucl-ex" + }, + { + "text": "Precision mass measurements of radioactive nuclei at JYFLTRAP: The Penning trap mass spectrometer JYFLTRAP was used to measure the atomic\nmasses of radioactive nuclei with an uncertainty better than 10 keV. The atomic\nmasses of the neutron-deficient nuclei around the N = Z line were measured to\nimprove the understanding of the rp-process path and the SbSnTe cycle.\nFurthermore, the masses of the neutron-rich gallium (Z = 31) to palladium (Z =\n46) nuclei have been measured. The physics impacts on the nuclear structure and\nthe r-process paths are reviewed. A better understanding of the nuclear\ndeformation is presented by studying the pairing energy around A = 100.", + "category": "nucl-ex" + }, + { + "text": "Low Energy Analyzing Powers in Pion-Proton Elastic Scattering: Analyzing powers of pion-proton elastic scattering have been measured at PSI\nwith the Low Energy Pion Spectrometer LEPS as well as a novel polarized\nscintillator target. Angular distributions between 40 and 120 deg (c.m.) were\ntaken at 45.2, 51.2, 57.2, 68.5, 77.2, and 87.2 MeV incoming pion kinetic\nenergy for pi+ p scattering, and at 67.3 and 87.2 MeV for pi- p scattering.\nThese new measurements constitute a substantial extension of the polarization\ndata base at low energies. Predictions from phase shift analyses are compared\nwith the experimental results, and deviations are observed at low energies.", + "category": "nucl-ex" + }, + { + "text": "Imperfect World of $\u03b2\u03b2$-decay Nuclear Data Sets?: The precision of double-beta ($\\beta\\beta$) decay experimental half-lives and\ntheir uncertainties is reevaluated. A complementary analysis of the decay\nuncertainties indicates deficiencies due to small size of statistical samples,\nand incomplete collection of experimental information. Further experimental and\ntheoretical efforts would lead toward more precise values of $\\beta\\beta$-decay\nhalf-lives and nuclear matrix elements.", + "category": "nucl-ex" + }, + { + "text": "Astrophysical factor for the neutron generator 13C(alpha,n)16O reaction\n in the AGB stars: The reaction 13C(alpha,n) is considered to be the main source of neutrons for\nthe s-process in AGB stars. At low energies the cross section is dominated by\nthe 1/2+ 6.356 MeV sub-threshold resonance in 17O whose contribution is\ndetermined with a very large uncertainty of ~1000% at stellar temperatures. In\nthis work we performed the most precise determination of the low-energy\nastrophysical S factor using the indirect asymptotic normalization (ANC)\ntechnique. The alpha-particle ANC for the sub-threshold state has been measured\nusing the sub-Coulomb alpha-transfer reaction (6Li,d). Using the determined ANC\nwe calculated S(0), which turns out to be an order of magnitude smaller than in\nthe NACRE compilation.", + "category": "nucl-ex" + }, + { + "text": "Search for particle-stable tetraneutrons in thermal fission of $^{235}$U: Background: The existence of a tetraneutron comprising four neutrons has long\nbeen debated.\n Purpose: Motivated by a recent observation of particle-stable tetraneutrons,\nwe investigated potential particle-stable tetraneutron emission in thermal\nneutron-induced $^{235}$U fission using a nuclear research reactor.\n Methods: We performed $\\gamma$-ray spectroscopy for a $^{88}$SrCO$_3$ sample\nirradiated in a reactor core. Stable $^{88}$Sr was expected to produce\n$^{91}$Sr by a tetraneutron-induced ($^4n$,n) reaction; hence, observation of\n$\\gamma$-rays followed by $\\beta$ decay of $^{91}$Sr would indicate\nparticle-stable tetraneutron emission.\n Results: The $\\gamma$-ray spectrum of an irradiated $^{88}$SrCO$_3$ sample\ndid not show any photopeak for $^{91}$Sr.\n Conclusion: The emission rate of particle-stable tetraneutrons, if they\nexist, is estimated to be lower than $8\\times 10^{-7}$ per fission at the 95%\nconfidence level, assuming the cross-sections of reactions induced by\nhypothetical particle-stable tetraneutrons.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the pn -> dK^+K^- total cross section close to threshold: Measurements of the pn -> p_spec dK^+K^- reaction, where p_spec is a\nspectator proton, have been undertaken at the Cooler Synchrotron COSY-Juelich\nby detecting a fast deuteron in coincidence with a K^+K^- pair in the ANKE\nfacility. Although the proton beam energy was fixed, the moving target neutron\nallowed values of the non-resonant quasi-free pn -> dK^+K^- total cross section\nto be deduced up to an excess energy epsilon ~ 100 MeV. Evidence is found for\nthe effects of K^-d and KKbar final state interactions. The comparison of these\ndata with those of pp -> ppK^+K^- and pp -> dK^+Kbar shows that all the total\ncross sections are very similar in magnitude.", + "category": "nucl-ex" + }, + { + "text": "Energy and system dependence of high-$p_T$ triggered two-particle\n near-side correlations: Previous studies have indicated that the near-side peak of high-$p_T$\ntriggered correlations can be decomposed into two parts, the \\textit{Jet} and\nthe \\textit{Ridge}. We present data on the yield per trigger of the\n\\textit{Jet} and the \\textit{Ridge} from $d+Au$, $Cu+Cu$ and $Au+Au$ collisions\nat $\\sqrt{s_{NN}}$ = 62.4 GeV and 200 GeV and compare data on the \\textit{Jet}\nto PYTHIA 8.1 simulations for $p+p$. PYTHIA describes the \\textit{Jet}\ncomponent up to a scaling factor, meaning that PYTHIA can provide a better\nunderstanding of the \\textit{Ridge} by giving insight into the effects of the\nkinematic cuts. We present collision energy and system dependence of the\n\\textit{Ridge} yield, which should help distinguish models for the production\nmechanism of the \\textit{Ridge}.", + "category": "nucl-ex" + }, + { + "text": "Fast-neutron induced pre-equilibrium reactions on 55Mn and 63,65Cu at\n energies up to 40 MeV: Excitation functions were measured for the $^{55}$Mn(n,2n)$^{54}$Mn,\n$^{55}$Mn(n,$\\alpha$)$^{52}$V, $^{63}$Cu(n,$\\alpha$)$^{60}$Co,\n$^{65}$Cu(n,2n)$^{64}$Cu, and $^{65}$Cu(n,p)$^{65}$Ni reactions from 13.47 to\n14.83 MeV. The experimental cross sections are compared with the results of\ncalculations including all activation channels for the stable isotopes of Mn\nand Cu, for neutron incident energies up to 50 MeV. Within the energy range up\nto 20 MeV the model calculations are most sensitive to the parameters related\nto nuclei in the early stages of the reaction, while the model assumptions are\nbetter established by analysis of the data in the energy range 20-40 MeV. While\nthe present analysis has taken advantage of both a new set of accurate measured\ncross sections around 14 MeV and the larger data basis fortunately available\nbetween 20 and 40 MeV for the Mn and Cu isotopes, the need of additional\nmeasurements below as well as above 40 MeV is pointed out. Keywords: 55Mn,\n63,65Cu, E$\\leq$40 MeV, Neutron activation cross section measurements, Nuclear\nreactions, Model calculations, Manganese, Copper", + "category": "nucl-ex" + }, + { + "text": "Some Striking New STAR Results: Recent high-statistics Au+Au and Cu+Cu runs at RHIC have provided a wealth of\nnew data that allow STAR to answer several outstanding questions regarding the\nnature of the hot, dense medium that is created in ultrarelativistic heavy-ion\ncollisions. However, the new data also raise new questions that require further\nstudy. Here, we focus on a few qualitatively new results presented by STAR for\nthe first time at Quark Matter `05.", + "category": "nucl-ex" + }, + { + "text": "System size dependence of associated yields in hadron-triggered jets: We present results on the system size dependence of high transverse momentum\ndi-hadron correlations at $\\sqrt{s_{NN}}$ = 200 GeV as measured by STAR at\nRHIC. Measurements in d+Au, Cu+Cu and Au+Au collisions reveal similar jet-like\ncorrelation yields at small angular separation ($\\Delta\\phi\\sim0$,\n$\\Delta\\eta\\sim0$) for all systems and centralities. Previous measurements have\nshown that the away-side yield is suppressed in heavy-ion collisions. We\npresent measurements of the away-side suppression as a function of transverse\nmomentum and centrality in Cu+Cu and Au+Au collisions. The suppression is found\nto be similar in Cu+Cu and Au+Au collisions at a similar number of\nparticipants. The results are compared to theoretical calculations based on the\nparton quenching model and the modified fragmentation model. The observed\ndifferences between data and theory indicate that the correlated yields\npresented here will provide important constraints on medium density profile and\nenergy loss model parameters.", + "category": "nucl-ex" + }, + { + "text": "Cosmic-ray Monte Carlo predictions for forward particle production in\n p-p, p-Pb, and Pb-Pb collisions at the LHC: We present and compare the predictions of various cosmic-ray Monte Carlo\nmodels for the energy (dE/deta) and particle (dN/deta) flows in p-p, p-Pb and\nPb-Pb collisions at sqrt(s) = 14, 8.8, and 5.5 TeV respectively, in the range\ncovered by forward LHC detectors like CASTOR or TOTEM (5.2<|eta|<6.6) and ZDC\nor LHCf (|eta|>8.1 for neutrals).", + "category": "nucl-ex" + }, + { + "text": "NA61/SHINE results on Bose-Einstein correlations: One of the main goals of NA61/SHINE is the investigation of the phase diagram\nof strongly interacting matter. NA61/SHINE observes collisions of various\nnuclei at different energies, allowing to study the same phenomena and\nobservables in vastly different conditions. One of the observables related to\nthe quark-hadron transition is the Bose-Einstein momentum correlation function\nof identical pions, related to the space-time structure of pion emission. In\nthis paper we report on such measurements in Be+Be collisions at an SPS beam\nmomentum of 150A GeV/c. Our correlation functions can be statistically well\ndescribed with Levy-distributed sources, hence we also study the mT dependence\nof the Levy source parameters, and discuss their possible interpretations.", + "category": "nucl-ex" + }, + { + "text": "The study of light nuclei production in different interactions at 4.2\n AGeV/c: Average multiplicity of light nuclei produced in different interactions at\n4.2A GeVc is studied as a function of centrality. A change in multiplicity is\nobserved with increase in the mass of projectile. In 12CC-interactions an\nunexpected increase in the multiplicity is seen for the most central events.\nThese measurements are compared with the predictions of Cascade and Fritiof\nModels which fail to account for the experimentally observed effects. In case\nof 12CC it is suggested that the inclusion of nuclear coalescence effect can be\nan explanatory reason for the differences between the experimental measurements\nand the models predictions.", + "category": "nucl-ex" + }, + { + "text": "Dynamical fission of the quasiprojectile and isospin equilibration for\n the system 80Kr+ 48 Ca at 35 MeV/nucleon: Experimental results concerning the dynamical fission of quasiprojectiles in\nsemiperipheral collisions for the system 80 Kr+ 48 Ca at 35 MeV/nucleon are\npresented. Data have been collected with four blocks of the FAZIA setup in the\nfirst physics experiment of the FAZIA Collaboration. The degree of isospin\nequilibration between the two fission fragments and its dependence on their\ncharge asymmetry is investigated. The data are compared with the results of the\nAMD model coupled to GEMINI as an afterburner, in order to get hints about the\ntimescale of the process.", + "category": "nucl-ex" + }, + { + "text": "Total and nuclear photoabsorption cross section of 52Cr in the energy\n range of 8 - 70 MeV: Total (atomic+nuclear) photoabsorption cross section of $^{52}Cr$ was for the\nfirst time measured in the energy range of 8-70 MeV. Experimental data was\nproduced with small statistic and systematic errors. The results deviate from\ncalculations of atomic cross section at photon energies above 40 MeV.\nPhotonuclear cross section in the region of the E1 giant dipole resonance (GDR)\nclearly exhibits three peaks at 18.9, 20.9 and 23.1 MeV. At higher energies,\nthe measured cross section hints a dip-peak structure at 40-48 MeV.", + "category": "nucl-ex" + }, + { + "text": "Meson Production in p+d Reactions: The production of neutral and charged pions as well as eta mesons is studied\nin the Delta and N* resonance region, respectively. Heavy A=3 recoils were\nmeasured with the GEM detector. The differential cross sections covering the\nfull angular range are compared with model calculations.", + "category": "nucl-ex" + }, + { + "text": "Backward-angle Exclusive pi0 Production above the Resonance Region: The proposed measurement is a dedicated study of the exclusive\nelectroproduction process,1H(e,e'p)pi0, in the backward-angle regime (u-channel\nprocess) above the resonance region. The produced pi0 is emitted 180 degrees\nopposite to the virtual-photon momentum. This study also aims to apply the\nwell-known Rosenbluth separation technique that provides the model-independent\ndifferential cross-sections at the never explored u-channel kinematics region.\nCurrently, the \"soft-hard transition\" in u-channel meson production remains an\ninteresting and unexplored subject. The available theoretical frameworks offer\ncompeting interpretations for the observed backward-angle cross section peaks.\nIn a \"soft\" hadronic Regge exchange description, the backward meson production\ncomes from the interference between nucleon exchange and the meson produced via\nre-scattering within the nucleon. Whereas in the \"hard\" GPD-like backward\ncollinear factorization regime, the scattering amplitude factorizes into a hard\nsubprocess amplitude and baryon to meson transition distribution amplitudes\n(TDAs), otherwise known as super skewed parton distributions (SuperSPDs). Both\nTDAs and SPDs are universal non-perturbative objects of nucleon structure\naccessible only through backward-angle kinematics. The separated cross\nsections:sigma_T,sigma_L and T/L ratio at Q2=2-6 GeV2, provide a direct test of\ntwo predictions from the TDA model. The magnitude and u-dependence of the\nseparated cross sections also provide a direct connection to the re-scattering\nRegge picture. The extracted interaction radius (from u-dependence) at\ndifferent Q2 can be used to study the soft-hard transition in the u-channel\nkinematics. The acquisition of these data will be an important step forward in\nvalidating the existence of a backward factorization scheme of the nucleon\nstructure function and establishing its applicable kinematic range.", + "category": "nucl-ex" + }, + { + "text": "Di-lepton production in p+p collisions at $\\sqrt{s_{_{NN}}} = 200$ GeV\n from STAR: The di-electron analysis for 200 GeV p+p collisions is presented in this\narticle. The cocktail simulations of di-eletrons from light flavor meson decays\nand heavy flavor decays are reported and compared with data. The perspectives\nfor di-lepton measurements in Au+Au collisions are discussed.", + "category": "nucl-ex" + }, + { + "text": "Production of deuterium, tritium, and $^3$He in central Pb+Pb collisions\n at 20A, 30A, 40A, 80A, and 158A GeV at the CERN SPS: Production of $d$, $t$, and $^3$He nuclei in central Pb+Pb interactions was\nstudied at five collision energies ($\\sqrt{s_{NN}}=$ 6.3, 7.6, 8.8, 12.3, and\n17.3 GeV) with the NA49 detector at the CERN SPS. Transverse momentum spectra,\nrapidity distributions, and particle ratios were measured. Yields are compared\nto predictions of statistical models. Phase-space distributions of light nuclei\nare discussed and compared to those of protons in the context of a coalescence\napproach. The coalescence parameters $B_2$ and $B_3$, as well as coalescence\nradii for $d$ and $^3$He were determined as a function of transverse mass at\nall energies.", + "category": "nucl-ex" + }, + { + "text": "Verification of detailed balance for $\u03b3$ absorption and emission in\n Dy isotopes: The photo-neutron cross sections of $^{162,163}\\rm{Dy}$ have been measured\nfor the first time in an energy region from the neutron threshold ($S_n$) up to\n$\\approx$ $13$~MeV. The ($\\gamma$,n) reaction was induced with\nquasi-monochromatic laser Compton-scattered $\\gamma$ rays, produced at the\nNewSUBARU laboratory. The corresponding $\\gamma$-ray strength functions\n($\\gamma$SF) have been calculated from the photo-neutron cross sections. The\ndata are compared to reanalyzed $\\gamma$SFs of $^{160-164}\\rm{Dy}$, which are\nmeasured below $S_n$. The excellent agreement with the photo-neutron data at\n$S_n$ confirms the principle of detailed balance. Thus, a complete $\\gamma$SF\nis established covering in total the energy region of 1 MeV $\\leq$ E$_{\\gamma}$\n$\\leq$ 13 MeV. These mid-shell well-deformed dysprosium isotopes all show\nscissors resonances with very similar structures. We find that our data predict\nthe same integrated scissors strength as ($\\gamma,\\gamma^\\prime$) data when\nintegrated over the same energy range, which shows that the scissors mode very\nlikely is consistent with the generalized Brink hypothesis. Finally, using the\n$\\gamma$SFs as input in the reaction code TALYS, we have deduced radiative\nneutron-capture cross sections and compared them to direct measurements. We\nfind a very good agreement within the uncertainties, which gives further\nsupport to the experimentally determined $\\gamma$SFs.", + "category": "nucl-ex" + }, + { + "text": "K*(892)$^{0}$ and $\u03a6$(1020) production in Pb-Pb collisions at\n $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV: The yields of the K*(892)$^{0}$ and $\\Phi$(1020) resonances are measured in\nPb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76 TeV through their hadronic\ndecays using the ALICE detector. The measurements are performed in multiple\ncentrality intervals at mid-rapidity (|$y$|<0.5) in the transverse-momentum\nranges 0.3 < $p_{\\rm T}$ < 5 GeV/$c$ for the K*(892)$^{0}$ and 0.5 < $p_{\\rm\nT}$ < 5 GeV/$c$ for the $\\Phi$(1020). The yields of K*(892)$^{0}$ are\nsuppressed in central Pb-Pb collisions with respect to pp and peripheral Pb-Pb\ncollisions (perhaps due to rescattering of its decay products in the hadronic\nmedium), while the longer lived $\\Phi$(1020) meson is not suppressed. These\nparticles are also used as probes to study the mechanisms of particle\nproduction. The shape of the $p_{\\rm T}$ distribution of the $\\Phi$(1020)\nmeson, but not its yield, is reproduced fairly well by hydrodynamic models for\ncentral Pb-Pb collisions. In central Pb-Pb collisions at low and intermediate\n$p_{\\rm T}$, the p/$\\Phi$(1020) ratio is flat in $p_{\\rm T}$, while the p/$\\pi$\nand $\\Phi$(1020)/$\\pi$ ratios show a pronounced increase and have similar\nshapes to each other. These results indicate that the shapes of the $p_{\\rm T}$\ndistributions of these particles in central Pb-Pb collisions are determined\npredominantly by the particle masses and radial flow. Finally, $\\Phi$(1020)\nproduction in Pb-Pb collisions is enhanced, with respect to the yield in pp\ncollisions and the yield of charged pions, by an amount similar to the\n$\\Lambda$ and $\\Xi$.", + "category": "nucl-ex" + }, + { + "text": "Centrality and transverse momentum dependence of inclusive J/$\u03c8$\n production at midrapidity in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02\n TeV: The inclusive J/$\\psi$ meson production in Pb-Pb collisions at a\ncenter-of-mass energy per nucleon-nucleon collision of $\\sqrt{s_{\\rm NN}}$ =\n5.02 TeV at midrapidity ($|y|$ < 0.9) is reported by the ALICE Collaboration.\nThe measurements are performed in the dielectron decay channel, as a function\nof event centrality and J/$\\psi$ transverse momentum $p_{\\rm T}$, down to\n$p_{\\rm T}$ = 0 GeV/$c$. The J/$\\psi$ mean transverse momentum $\\langle p_{\\rm\nT} \\rangle$ and $r_{\\rm AA}$ ratio, defined as $\\langle p^{\\rm 2}_{\\rm T}\n\\rangle_{\\rm PbPb}/\\langle p^{\\rm 2}_{\\rm T} \\rangle_{\\rm pp}$, are evaluated.\nBoth observables show a centrality dependence decreasing towards central\n(head-on) collisions. The J/$\\psi$ nuclear modification factor $R_{\\rm AA}$\nexhibits a strong $p_{\\rm T}$ dependence with a large suppression at high\n$p_{\\rm T}$ and an increase to unity for decreasing $p_{\\rm T}$. When\nintegrating over the measured momentum range $p_{\\rm T}$ < 10 GeV/$c$, the\nJ/$\\psi$ $R_{\\rm AA}$ shows a weak centrality dependence. Each measurement is\ncompared with results at lower center-of-mass energies and with ALICE\nmeasurements at forward rapidity, as well as to theory calculations. All\nreported features of the J/$\\psi$ production at low $p_{\\rm T}$ are consistent\nwith a dominant contribution to the J/$\\psi$ yield originating from charm quark\n(re)combination.", + "category": "nucl-ex" + }, + { + "text": "Analysis of 2-Body Central Events for $^{129}Xe+^{nat}Sn$ from $8A$\n $MeV$ up to $18A$ $MeV$ and for $^{129}Xe+^{197}Au$ at $15A$ $MeV$ and $18A$\n $MeV$: A study of medium-mass heavy-ion reactions leading to two fragments in the\nexit channel from barrier to 18A MeV is proposed. A special focus is made on\nfission and quasi-fission for events with two fragments ($Z\\geq10$) in the exit\nchannel selected. Reactions induced by $^{129}Xe$ projectiles on $^{nat}Sn$ and\non $^{197}Au$ at energies ranging from $8A$ MeV to $18A$ MeV were analyzed.\nUsing the fragment ($Z\\geq10$) multiplicity equal to 2, fission and\nquasi-fission events were studied for the lowest beam energies using the\nfission fragment charge distributions, the total kinetic energy distribution\n(TKE) and its standard deviation $\\sigma_{TKE}$. For the lighter system it is\nstill possible to observe fission events from incomplete fusion. At variance,\nfor the heavier system, Xenon on gold target only quasi-fission is evidenced.\nThe study of the events characterized by two fragments in the final channel\nshows that fission, related to fusion in the entrance channel, disappears\naround 20A MeV for both systems. At lower energies (8A, 12A and 15A MeV) for\nthe Sn target, an evolution with increasing energies towards an asymmetric\nfission mode is displayed in the fragment charge distributions. This trend can\nbe attributed to the increasing angular momentum as indicated by the\nout-of-plane angular distribution for light charged particles. The same effect\nis also observed in the case of the gold target at 15A MeV. However, for this\nheavier system, a strong memory of the entrance channel leading to\nquasi-fission is evidenced. A comparison with the Viola systematics, moreover,\nshows a deviation, greater for the heavier system than for $^{129}Xe+^{nat}Sn$\nsystem. A complete understanding of the above results would certainly require\nprecise model calculations at these energies.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the beam-helicity asymmetry $I^{\\odot}$ in the\n photoproduction of $\u03c0^0\u03c0^{\\pm}$-pairs off protons and off neutrons: Beam-helicity asymmetries have been measured at the MAMI accelerator in Mainz\nfor the photoproduction of mixed-charge pion pairs in the reactions\n$\\boldsymbol{\\gamma}p\\rightarrow n\\pi^0\\pi^+$ off free protons and\n$\\boldsymbol{\\gamma}d\\rightarrow (p)p\\pi^0\\pi^-$ and\n$\\boldsymbol{\\gamma}d\\rightarrow (n)n\\pi^0\\pi^+$ off quasi-free nucleons bound\nin the deuteron for incident photon energies up to 1.4 GeV. Circularly\npolarized photons were produced from bremsstrahlung of longitudinally polarized\nelectrons and tagged with the Glasgow-Mainz magnetic spectrometer. The charged\npions, recoil protons, recoil neutrons, and decay photons from $\\pi^0$ mesons\nwere detected in the 4$\\pi$ electromagnetic calorimeter composed of the Crystal\nBall and TAPS detectors. Using a complete kinematic reconstruction of the final\nstate, excellent agreement was found between the results for free and\nquasi-free protons, suggesting that the quasi-free neutron results are also a\nclose approximation of the free-neutron asymmetries. A comparison of the\nresults to the predictions of the Two-Pion-MAID reaction model shows that the\nreaction mechanisms are still not well understood, in particular at low\nincident photon energies in the second nucleon-resonance region.", + "category": "nucl-ex" + }, + { + "text": "The first candidate for chiral nuclei in the $A\\sim80$ mass region:\n $^{80}$Br: Excited states of $^{80}$Br have been investigated via the\n$^{76}$Ge($^{11}$B, $\\alpha$3n) and $^{76}$Ge($^{7}$Li, 3n) reactions and a new\n$\\Delta I$ = 1 band has been identified which resides $\\sim$ 400 keV above the\nyrast band. Based on the experimental results and their comparison with the\ntriaxial particle rotor model calculated ones, a chiral character of the two\nbands within the $\\pi g_{9/2}\\otimes \\nu g_{9/2}$ configuration is proposed,\nwhich provides the first evidence for chirality in the $A\\sim80$ region.", + "category": "nucl-ex" + }, + { + "text": "Polarisation of the omega meson in the pd-->3He+omega reaction at 1360\n and 1450 MeV: The tensor polarisation of omega mesons produced in the pd-->3He+omega\nreaction has been studied at two energies near threshold. The 3He nuclei were\ndetected in coincidence with the pi0pi+pi- or pi0gamma decay products of the\nomega. In contrast to the case of phi meson production, the omega mesons are\nfound to be unpolarised. This brings into question the applicability of the\nOkubo-Zweig-Iizuka rule when comparing the production of vector mesons in low\nenergy hadronic reactions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of leading charged-particle jet properties in p--Pb\n collisions at $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV with ALICE: Jets are collimated sprays of particles produced from the fragmentation and\nhadronization of hard-scattered partons in high energy hadronic and nuclear\ncollisions. Jet properties are sensitive to details of parton showering\nprocesses and are expected to be modified in the presence of a dense partonic\nmedium. Measurement of intra-jet properties in p--Pb collisions will help to\ninvestigate cold nuclear matter effects and enrich our current understanding of\nparticle production in such collision systems. In this work, we present the\nmeasurement of leading charged-particle jet properties, namely the mean\ncharged-particle multiplicity and the fragmentation functions, in the range of\njet $p_{\\rm T}$ 10 -- 100 GeV/c at midrapidity in minimum bias p--Pb collisions\nat $\\sqrt{s_{\\rm NN}}$ = 5.02 TeV with ALICE. Results are compared with\ntheoretical model predictions.", + "category": "nucl-ex" + }, + { + "text": "Coulomb excitation of 73Ga: The B(E2; Ii -> If) values for transitions in 71Ga and 73Ga were deduced from\na Coulomb excitation experiment at the safe energy of 2.95 MeV/nucleon using\npost-accelerated beams of 71,73Ga at the REX-ISOLDE on-line isotope mass\nseparator facility. The emitted gamma rays were detected by the\nMINIBALL-detector array and B(E2; Ii->If) values were obtained from the yields\nnormalized to the known strength of the 2+ -> 0+ transition in the 120Sn\ntarget. The comparison of these new results with the data of less neutron-rich\ngallium isotopes shows a shift of the E2 collectivity towards lower excitation\nenergy when adding neutrons beyond N = 40. This supports conclusions from\nprevious studies of the gallium isotopes which indicated a structural change in\nthis isotopical chain between N = 40 and N = 42. Combined with recent\nmeasurements from collinear laser spectroscopy showing a 1/2- spin and parity\nfor the ground state, the extracted results revealed evidence for a 1/2-; 3/2-\ndoublet near the ground state in 73 31Ga42 differing by at most 0.8 keV in\nenergy.", + "category": "nucl-ex" + }, + { + "text": "Characterizing the initial conditions of heavy-ion collisions at the LHC\n with mean transverse momentum and anisotropic flow correlations: Correlations between mean transverse momentum $[p_{\\rm T}]$ and anisotropic\nflow coefficients $v_{\\rm 2}$ or $v_{\\rm 3}$ are measured as a function of\ncentrality in Pb$-$Pb and Xe$-$Xe collisions at $\\sqrt{s_{\\rm NN}} = 5.02$ TeV\nand 5.44 TeV, respectively, with ALICE. In addition, the recently proposed\nhigher-order correlation between $[p_{\\rm T}]$, $v_{\\rm 2}$, and $v_{\\rm 3}$ is\nmeasured for the first time, which shows an anticorrelation for the presented\ncentrality ranges. These measurements are compared with hydrodynamic\ncalculations using IP-Glasma and $\\rm T_{R}ENTo$ initial-state shapes, the\nformer based on the Color Glass Condensate effective theory with gluon\nsaturation, and the latter a parameterized model with nucleons as the relevant\ndegrees of freedom. The data are better described by the IP-Glasma rather than\nthe $\\rm T_{R}ENTo$ based calculations. In particular, Trajectum and JETSCAPE\npredictions, both based on the $\\rm T_{R}ENTo$ initial state model but with\ndifferent parameter settings, fail to describe the measurements. As the\ncorrelations between $[p_{\\rm T}]$ and $v_{\\rm n}$ are mainly driven by the\ncorrelations of the size and the shape of the system in the initial state,\nthese new studies pave a novel way to characterize the initial state and help\npin down the uncertainty of the extracted properties of the quark$-$gluon\nplasma recreated in relativistic heavy-ion collisions.", + "category": "nucl-ex" + }, + { + "text": "Latest CMS Heavy-Ion Results on Jets: Jet studies provide an experimental method to explore the features of energy\nloss in the strongly interacting quark-gluon plasma. Recent jet results from\n2.76 TeV PbPb and pp collisions measured with the CMS detector are presented.\nJets in the most head-on (central) PbPb collisions are quenched in comparison\nto pp, and the jets fragment in different ways in the two systems. Measurements\nfrom pPb collisions at 5.02 TeV show that the jet and charged particle\nsuppression seen in central PbPb measurements are not due to initial state\nnuclear effects.", + "category": "nucl-ex" + }, + { + "text": "Comparison of fragment partitions production in peripheral and central\n collisions: Ensembles of single-source events, produced in peripheral and central\ncollisions and correponding respectively to quasi-projectile and quasi-fusion\nsources, are analyzed. After selections on fragment kinematic properties,\nexcitation energies of the sources are derived using the calorimetric method\nand the mean behaviour of fragments of the two ensembles are compared.\nDifferences observed in their partitions, especially the charge asymmetry, can\nbe related to collective energy deposited in the systems during the collisions.", + "category": "nucl-ex" + }, + { + "text": "Decay modes of $^{10}$C nuclei unbound state: Unbound states of $^{10}$C nuclei produced as quasi-projectiles in\n$^{12}$C+$^{24}$Mg collisions at E/A = 53 and 95 MeV are studied with the Indra\ndetector array. Multi-particle correlation function analyses provide\nexperimental evidence of sequential de-excitation mechanisms through the\nproduction of intermediate $^{9}$B, $^{6}$Be and $^{8}$Be unbound nuclei. The\nrelative contributions of different decay sequences to the total decay width of\nthe explored states is estimated semi-quantitatively. The obtained results show\nthat heavy-ion collisions can be used as a tool to access spectroscopic\ninformation about exotic nuclei.", + "category": "nucl-ex" + }, + { + "text": "Shape and Angular Distribution of the 4.438-MeV Line from Proton\n Inelastic Scattering off 12C: The emission of the 4.438-MeV gamma-ray line in proton inelastic scattering\noff 12C has been investigated in detail. The correlated scattering and emission\nprocess is described independently for the direct reaction mechanism and for\nthe compound-nucleus (CN) component. The inelastic scattering process for\ndirect reactions is treated with a coupled-channels nuclear reaction code,\nwhile the CN component is described as a superposition of separate resonances\nwith definite spin and parity, treated with the angular momentum coupling\ntheory. The calculations are compared to a comprehensive data set on measured\nline shapes and angular distributions in the proton energy range E_p = 5.44 -\n25.0 MeV. In the range E_p ~ 12 - 25 MeV a good agreement is obtained in\ncalculations assuming direct reactions with only a negligible part of CN\nreactions. At lower energy, the data are reproduced by incoherent sums of the\ndirect component with typically one CN resonance. Based on these results, the\nprospectives for line shape calculations applied to solar flares and gamma-ray\nemission in proton radiotherapy are discussed.", + "category": "nucl-ex" + }, + { + "text": "Forward-Backward Multiplicity Correlations in Au+Au Collisions at\n $\\sqrt{s_{NN}}$ = 200 Gev: The study of correlations among particles produced in different rapidity\nregions may provide understanding of the mechanisms of particle production.\nCorrelations that extend over a longer range are observed in hadron-hadron\ninteractions only at higher energies. Results for short and long-range\nmultiplicity correlations (Forward-Backward) are presented for Au+Au collisions\nat $\\sqrt{s_{NN}}$ = 200 GeV. The growth of long range correlations are\nobserved as a function of the pseudorapidity gap in central Au+Au collisions.\nThe Dual Parton model and Color Glass Condensate phenomenology have been\nexplored to understand the origin of long range correlations.", + "category": "nucl-ex" + }, + { + "text": "Strong Multi-step Interference Effects in 12C(d,p) to the 9/2+ State in\n 13C: The population of the 9.50 MeV 9/2+ resonance in 13C by single neutron\ntransfer reactions is expected to be dominated by the two-step route through\nthe 12C 2+ (4.44 MeV) state, with another possible contribution via the\nstrongly excited 3- (9.64 MeV) resonance in 12C. However, we find that a good\ndescription of the angular distribution for population of this state via the\n12C(d,p)13C reaction is only possible when both direct 0+ x g_9/2 and two-step\n(via the 4.44 MeV 12C 2+ state) 2+ x d_5/2 paths are included in a coupled\nreaction channel calculation. While the calculated angular distribution is\nalmost insensitive to the presence of the two-step path via the 9.64 MeV 12C 3-\nresonance, despite a much greater contribution to the wave function from the 3-\nx f_7/2 configuration, its inclusion is required to fit the details of the\nexperimental angular distribution. The very large interference between the\nvarious components of the calculations, even when these are small, arises\nthrough the ``kinematic'' effect associated with the different transfer routes.", + "category": "nucl-ex" + }, + { + "text": "Impact of $^{16}$O($\u03b3$,$\u03b1$)$^{12}$C measurements on the\n $^{12}$C($\u03b1,\u03b3$)$^{16}$O astrophysical reaction rate: The $^{12}$C($\\alpha,\\gamma$)$^{16}$O reaction, an important component of\nstellar helium burning, plays a key role in nuclear astrophysics. It has direct\nimpact on the evolution and final state of massive stars, while also\ninfluencing the elemental abundances resulting from nucleosynthesis in such\nstars. Providing a reliable estimate for the energy dependence of this reaction\nat stellar helium burning temperatures has been a major goal for the field. In\nthis work, we study the role of potential new measurements of the inverse\nreaction, $^{16}$O($\\gamma,\\alpha$)$^{12}$C, in reducing the overall\nuncertainty. A multilevel R-matrix analysis is used to make extrapolations of\nthe astrophysical S factor for this reaction to the stellar energy of 300 keV.\nThe statistical precision of the S-factor extrapolation is determined by\nperforming multiple fits to existing E1 and E2 ground state capture data,\nincluding the impact of possible future measurements of the\n$^{16}$O($\\gamma,\\alpha$)$^{12}$C reaction. In particular, we consider a\nproposed JLab experiment that will make use of a high-intensity low-energy\nbremsstrahlung beam that impinges on an oxygen-rich single-fluid bubble chamber\nin order to measure the total cross section for the inverse reaction. The\nimportance of low energy data as well as high precision data is investigated.", + "category": "nucl-ex" + }, + { + "text": "Effects of centrality fluctuation and deuteron formation on proton\n number cumulant in Au+Au collisions at $\\sqrt{s_\\mathrm{NN}}$ = 3 GeV from\n JAM model: We studied the effects of centrality fluctuation and deuteron formation on\nthe cumulants ($C_n$) and correlation functions ($\\kappa_n$) of protons up to\nsixth order in most central ($b<3$ fm) Au+Au collisions at\n$\\sqrt{s_\\mathrm{NN}}$ = 3 GeV from a microscopic transport model (JAM). The\nresults are presented as a function of rapidity acceptance within transverse\nmomentum $0.4$ 3.5 GeV/$c$, which indicates\nthat beauty quark interacts with the hot-dense medium with depositing its\nenergy and is consistent with the mass-dependent energy loss scenario. For the\nfirst time, the non-zero electron $v_2$ from beauty hadron decays ($v_2^{\\rm\nb\\rightarrow e}$) at $p_{\\rm T}$ $>$ 3.0 GeV/$c$ is observed and shows smaller\nelliptic flow compared with that from charmed hadron decays at $p_{\\rm T}$ $<$\n4.0 GeV/$c$. At 2.5 GeV/$c$ $<$ $p_{\\rm T}$ $<$ 4.5 GeV/$c$, $v_2^{\\rm\nb\\rightarrow e}$ is smaller than a number-of-constituent-quark (NCQ) scaling\nhypothesis. This suggests that beauty quark is unlikely thermalized and too\nheavy to be moved in a partonic collectivity in heavy-ion collisions at the\nRHIC energy.", + "category": "nucl-ex" + }, + { + "text": "High Resolution Hypernuclear Spectroscopy at Jefferson Lab Hall A: The characteristics of the Jefferson Lab electron beam, together with those\nof the experimental equipment, offer a unique opportunity to study hypernuclear\nspectroscopy via electromagnetic induced reactions. Experiment 94-107 started a\nsystematic study on 1p-shell targets, $^{12}C$, $^{9}Be$ and $^{16}O$. For\n$^{12}C$ for the first time measurable strength in the core-excited part of the\nspectrum between the ground state and the p state was shown in\n$^{12}_{\\Lambda}B$ spectrum. A high-quality $^{16}_{\\Lambda}N$ spectrum was\nproduced for the first time with sub-MeV energy resolution. A very precise\n$\\Lambda$ binding energy value for $^{16}_{\\Lambda}N$, calibrated against the\nelementary $(e,e'K^+)$ reaction on hydrogen, has also been obtained.\n$^{9}_{\\Lambda}Li$ spectrum shows some disagreement in strength for the second\nand third doublet with respect to the theory.", + "category": "nucl-ex" + }, + { + "text": "Improved precision on the experimental E0 decay branching ratio of the\n Hoyle state: Stellar carbon synthesis occurs exclusively via the $3\\alpha$ process, in\nwhich three $\\alpha$ particles fuse to form $^{12}$C in the excited Hoyle\nstate, followed by electromagnetic decay to the ground state. The Hoyle state\nis above the $\\alpha$ threshold, and the rate of stellar carbon production\ndepends on the radiative width of this state. The radiative width cannot be\nmeasured directly, and must instead be deduced by combining three separately\nmeasured quantities. One of these quantities is the $E0$ decay branching ratio\nof the Hoyle state, and the current $10$\\% uncertainty on the radiative width\nstems mainly from the uncertainty on this ratio. The $E0$ branching ratio was\ndeduced from a series of pair conversion measurements of the $E0$ and $E2$\ntransitions depopulating the $0^+_2$ Hoyle state and $2^+_1$ state in $^{12}$C,\nrespectively. The excited states were populated by the $^{12}$C$(p,p^\\prime)$\nreaction at 10.5 MeV beam energy, and the pairs were detected with the\nelectron-positron pair spectrometer, Super-e, at the Australian National\nUniversity. The deduced branching ratio required knowledge of the proton\npopulation of the two states, as well as the alignment of the $2^+_1$ state in\nthe reaction. For this purpose, proton scattering and $\\gamma$-ray angular\ndistribution experiments were also performed. An $E0$ branching ratio of\n$\\Gamma^{E0}_{\\pi}/\\Gamma=8.2(5)\\times10^{-6}$ was deduced in the current work,\nand an adopted value of $\\Gamma^{E0}_{\\pi}/\\Gamma=7.6(4)\\times10^{-6}$ is\nrecommended based on a weighted average of previous literature values and the\nnew result. The new recommended value for the $E0$ branching ratio is about 14%\nlarger than the previous adopted value of\n$\\Gamma^{E0}_{\\pi}/\\Gamma=6.7(6)\\times10^{-6}$, while the uncertainty has been\nreduced from 9% to 5%.", + "category": "nucl-ex" + }, + { + "text": "Event-by-event mean p_T fluctuations in pp and Pb-Pb collisions at the\n LHC: The ALICE detector at the LHC is used to study the properties of the\nQuark-Gluon Plasma produced in heavy-ion collisions. As a reference\nmeasurement, also the analysis of proton-proton (pp) collisions is very\nimportant. In the study presented here, event-by-event fluctuations of the mean\ntransverse momentum are analysed in pp collisions at sqrt(s) = 0.9, 2.76 and 7\nTeV, and Pb-Pb collisions at sqrt(s_NN) = 2.76 TeV as a function of the\ncharged-particle multiplicity. In both systems, dynamical fluctuations beyond\nthe statistical expectation are observed. In pp collisions, no significant\ndependence on collision energy is found, even in comparison to inclusive\nresults at much lower collision energies. Likewise, central A-A collisions show\nonly little dependence on collision energy. The multiplicity dependence\nobserved in peripheral Pb-Pb data is in agreement with that in pp collisions.\nGoing to more central Pb-Pb collisions, a clear deviation from this trend is\nfound, reaching a significant reduction of the fluctuations in most central\ncollisions. Comparisons to Monte Carlo event generators show good agreement in\npp, but rather large differences in Pb-Pb collisions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of global polarization of \u039b hyperons in few-GeV\n heavy-ion collisions: The global polarization of {\\Lambda} hyperons along the total orbital angular\nmomentum of a relativistic heavy-ion collision is presented based on the high\nstatistics data samples collected in Au+Au collisions at \\sqrt{s_{NN}} = 2.4\nGeV and Ag+Ag at 2.55 GeV with the High-Acceptance Di-Electron Spectrometer\n(HADES) at GSI, Darmstadt. This is the first measurement below the strangeness\nproduction threshold in nucleon-nucleon collisions. Results are reported as a\nfunction of the collision centrality as well as a function of the hyperon\ntransverse momentum (p_T) and rapidity (y_{CM}) for the range of centrality\n0--40%. We observe a strong centrality dependence of the polarization with an\nincreasing signal towards peripheral collisions. For mid-central (20--40%)\ncollisions the polarization magnitudes are (%) = 6.8 \\pm 1.3\n(stat.) \\pm 2.1 (syst.) for Au+Au and (%) = 6.2 \\pm 0.4 (stat.)\n\\pm 0.6 (syst.) for Ag+Ag, which are the largest values observed so far. This\nobservation thus provides a continuation of the increasing trend previously\nobserved by STAR and contrasts expectations from recent theoretical\ncalculations predicting a maximum in the region of collision energies about 3\nGeV. The observed polarization is of a similar magnitude as predicted by 3D\nfluid dynamics and the UrQMD plus thermal vorticity model and significantly\nabove results from the AMPT model.", + "category": "nucl-ex" + }, + { + "text": "Characterizing the mechanism(s) of heavy element synthesis: A review of the current state of our understanding of complete fusion\nreaction mechanisms is presented, from the perspective of an experimentalist.\nFor complete fusion reactions, the overall uncertainties in predicting heavy\nelement synthesis cross sections are examined in terms of the uncertainties\nassociated with the calculations of capture cross sections, fusion\nprobabilities and survival probabilities.", + "category": "nucl-ex" + }, + { + "text": "Two-particle transverse momentum correlations in pp and p-Pb collisions\n at energies available at the CERN Large Hadron Collider: Two-particle transverse momentum differential correlators, recently measured\nin Pb--Pb collisions at energies available at the CERN Large Hadron Collider\n(LHC), provide an additional tool to gain insights into particle production\nmechanisms and infer transport properties, such as the ratio of shear viscosity\nto entropy density, of the medium created in Pb-Pb collisions. The longitudinal\nlong-range correlations and the large azimuthal anisotropy measured at low\ntransverse momenta in small collision systems, namely pp and p-Pb, at LHC\nenergies resemble manifestations of collective behaviour. This suggests that\nlocally equilibrated matter may be produced in these small collision systems,\nsimilar to what is observed in Pb-Pb collisions. In this work, the same\ntwo-particle transverse momentum differential correlators are exploited in pp\nand p-Pb collisions at $\\sqrt{s} = 7$ TeV and $\\sqrt{s_{\\rm NN}} = 5.02$ TeV,\nrespectively, to seek evidence for viscous effects. Specifically, the strength\nand shape of the correlators are studied as a function of the produced particle\nmultiplicity to identify evidence for longitudinal broadening that might reveal\nthe presence of viscous effects in these smaller systems. The measured\ncorrelators and their evolution from pp and p--Pb to Pb--Pb collisions are\nadditionally compared to predictions from Monte Carlo event generators, and the\npotential presence of viscous effects is discussed.", + "category": "nucl-ex" + }, + { + "text": "PHENIX Direct Photons in 200 GeV p+p and Au+Au Collisions: We present the first positive direct photon results in Au+Au at sqrt{s_NN} =\n200 GeV along with initial p+p results at the same energy. The p+p result is\nfound to be consistent with NLO perturbative QCD predictions within its large\nuncertainties. In central Au+Au collisions, an excess over expected background\nas large as 200-300% is observed from p_T = 4-12 GeV/c. This large signal is\nshown to be consistent with the scaled pQCD photon prediction, together with\nsuppression of meson background sources.", + "category": "nucl-ex" + }, + { + "text": "Statistical sensitivity of the nEDM apparatus at PSI to neutron\n mirror-neutron oscillations: The neutron and its hypothetical mirror counterpart, a sterile state\ndegenerate in mass, could spontaneously mix in a process much faster than the\nneutron $\\beta$-decay. Two groups have performed a series of experiments in\nsearch of neutron - mirror-neutron ($n-n'$) oscillations. They reported no\nevidence, thereby setting stringent limits on the oscillation time\n$\\tau_{nn'}$. Later, these data sets have been further analyzed by Berezhiani\net al.(2009-2017), and signals, compatible with $n-n'$ oscillations in the\npresence of mirror magnetic fields, have been reported. The Neutron Electric\nDipole Moment Collaboration based at the Paul Scherrer Institute performed a\nnew series of experiments to further test these signals. In this paper, we\ndescribe and motivate our choice of run configurations with an optimal filling\ntime of $29~$s, storage times of $180~$s and $380~$s, and applied magnetic\nfields of $10~\\mu$T and $20~\\mu$T. The choice of these run configurations\nensures a reliable overlap in settings with the previous efforts and also\nimproves the sensitivity to test the signals. We also elaborate on the\ntechnique of normalizing the neutron counts, making such a counting experiment\nat the ultra-cold neutron source at the Paul Scherrer Institute possible.\nFurthermore, the magnetic field characterization to meet the requirements of\nthis $n-n'$ oscillation search is demonstrated. Finally, we show that this\neffort has a statistical sensitivity comparable to the current leading\nconstraints for $n-n'$ oscillations.", + "category": "nucl-ex" + }, + { + "text": "Experimental conditions for the gamma optical scattering: This work discusses the possibility of observation of nuclear multiphoton\nprocesses in which the interaction of a gamma ray photon with a nucleus takes\nplace simultaneously with the interaction of a radio-frequency photon.", + "category": "nucl-ex" + }, + { + "text": "Prototype Performance of Novel Muon Telescope Detector at STAR: Research on a large-area, cost-effective Muon Telescope Detector has been\ncarried out for RHIC and for next generation detectors at future QCD Lab. We\nutilize state-of-the-art multi-gap resistive plate chambers with large modules\nand long readout strips in detector design \\cite{MTDLDRD}. The results from\ncosmic ray and beam test will be presented to address intrinsic timing and\nspatial resolution for a Long-MRPC. The prototype performance of a novel muon\ntelescope detector at STAR will be reported, including muon identification\ncapability, timing and spatial resolution.", + "category": "nucl-ex" + }, + { + "text": "Data on neutron-neutron scattering length extracted in the n+2H-->n+n+p\n reaction at 60 MeV: $^{1}S_{0}$ \\textit{nn}-scattering length has been measured in the\n\\textit{nd}-breakup reaction at 60 MeV. The experiment was performed in the\nfinal state interaction geometry with registration of all three secondary\nparticles. The scattering length $a_{nn} = -16.3 \\pm 0.5$~fm was obtained from\na comparison of the experimental dependence of the \\textit{nd}-breakup yield on\nthe relative energy of \\textit{nn}-pair with the simulation results. An\nanalysis of this value of scattering length together with the data obtained in\nother experiments on \\textit{nd}- and \\textit{dd}-breakup confirms the\nhypothesis about the influence of $3N$-forces on the values of\n\\textit{nn}-interaction parameters extracted in these reactions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of Open Heavy Flavor Production with Single Muons in p+p and\n d+Au Collisions at RHIC: Heavy flavor production in hadronic collisions is dominated by gluonic\nprocesses and so is a sensitive probe of the gluon structure function in the\nnucleon and its modification in nuclei. A study of heavy flavor production in\np+p and d+Au collisions in various kinematic regions presents an opportunity to\nprobe cold nuclear medium effects; parton shadowing, color glass condensate,\ninitial state energy loss, and coherent multiple scattering in final state\ninteractions. The PHENIX muon arms cover both forward and backward directions\nin the rapidity range of $1.2 < |\\eta| < 2.4$. We investigate single muon\nproduction from open heavy flavor and light mesons decay in p+p and d+Au\ncollisions at forward and backward rapidity.", + "category": "nucl-ex" + }, + { + "text": "Open heavy flavour production via semi-leptonic decay muons in lead lead\n collisions at $\\sqrtsnn = 2.76$ \\TeV with the ATLAS detector at the LHC: Measurements of heavy quark production and suppression in ultra-relativistic\nnuclear collisions probe the interactions of heavy quarks with the hot, dense\nmedium created in the collisions. ATLAS has measured heavy quark production in\n$\\sqrtsnn = 2.76$ \\TeV \\PbPb collisions via semi-leptonic decays of open heavy\nflavour hadrons to muons. Results are presented for the per-event muon yield as\na function of muon transverse momentum, \\pT, over the range of $4 < \\pT < 14$\n\\GeV. The centrality dependence of the muon yields is characterized by the\n\"central to peripheral\" ratio, \\Rcp. Muon production is suppressed by\napproximately a factor of two in central collisions relative to peripheral\ncollisions. Within the experimental errors, the observed suppression is\nindependent of muon \\pT for all centralities.", + "category": "nucl-ex" + }, + { + "text": "Fusion excitation function revisited: We report on a comprehensive systematics of fusion-evaporation and/or\nfusion-fission cross sections for a very large variety of systems over an\nenergy range 4-155 A.MeV. Scaled by the reaction cross sections, fusion cross\nsections do not show a universal behavior valid for all systems although a high\ndegree of correlation is present when data are ordered by the system mass\nasymmetry.For the rather light and close to mass-symmetric systems the main\ncharacteristics of the complete and incomplete fusion excitation functions can\nbe precisely determined. Despite an evident lack of data above 15A.MeV for all\nheavy systems the available data suggests that geometrical effects could\nexplain the persistence of incomplete fusion at incident energies as high as\n155A.MeV.", + "category": "nucl-ex" + }, + { + "text": "Inclusive Jet Spectra in p-Pb Collisions at ALICE: Jet suppression has been observed in central heavy ion collisions. This\nsuppression is attributed to partonic energy loss in the Quark Gluon Plasma\n(QGP) formed in such collisions. However, this measurement is influenced by all\nstages of the collision. It is expected that in p-Pb collisions similar initial\nconditions occur as in Pb-Pb collisions without creating a QGP, allowing\nmodification to the jet spectra due to cold nuclear matter effects to be\nquantified. Inclusive jet spectra in p-Pb collisions at $\\sqrt{s_{\\rm NN}} =\n5.02$ TeV measured by ALICE are presented. Jets are reconstructed via the\nanti-k$_{\\rm T}$ algorithm with different resolution parameters by combining\ncharged tracks measured in the ALICE tracking system with the neutral energy\ndeposited in the electromagnetic calorimeter. The jet spectra can be used to\ndetermine a nuclear modification factor $R_{\\rm pPb}$ while the jet profile in\np-Pb is studied by dividing spectra measured with different resolution\nparameters and comparing to the same ratio measured in pp collisions.", + "category": "nucl-ex" + }, + { + "text": "Charged pion form factor between Q^2=0.60 and 2.45 GeV^2. II.\n Determination of, and results for, the pion form factor: The charged pion form factor, Fpi(Q^2), is an important quantity which can be\nused to advance our knowledge of hadronic structure. However, the extraction of\nFpi from data requires a model of the 1H(e,e'pi+)n reaction, and thus is\ninherently model dependent. Therefore, a detailed description of the extraction\nof the charged pion form factor from electroproduction data obtained recently\nat Jefferson Lab is presented, with particular focus given to the dominant\nuncertainties in this procedure. Results for Fpi are presented for\nQ^2=0.60-2.45 GeV^2. Above Q^2=1.5 GeV^2, the Fpi values are systematically\nbelow the monopole parameterization that describes the low Q^2 data used to\ndetermine the pion charge radius. The pion form factor can be calculated in a\nwide variety of theoretical approaches, and the experimental results are\ncompared to a number of calculations. This comparison is helpful in\nunderstanding the role of soft versus hard contributions to hadronic structure\nin the intermediate Q^2 regime.", + "category": "nucl-ex" + }, + { + "text": "Nuclear excitation functions from 40-200 MeV proton irradiation of\n terbium: Nuclear formation cross sections are reported for 26 radionuclides, measured\nwith 40 to 200 MeV proton irradiations of terbium foils. These data are\nrelevant to the production of medically relevant radionuclides (e.g., 152Tb,\n155Tb, 155Eu, and 156Eu) and to ongoing efforts to characterize stellar\nnucleosynthesis routes passing through long-lived intermediaries (e.g., 153Gd).\nComputational predictions from the ALICE2011, CEM03.03, Bertini, and INCL+ABLA\ncodes are compared with newly measured data to contribute to the ongoing\nprocess of code development, and yields are calculated for selected\nradionuclides using measured data.", + "category": "nucl-ex" + }, + { + "text": "Nonextensive statistics in spin precession: Many experiments utilize the precession of trapped particles in magnetic\nfields to perform high precision measurements. It had been presumed that after\nfree precession, initially polarized particles will form a Gaussian phase\ndistribution in the plane of precession. We show that trapped particles in the\npresence of magnetic field gradients and electric fields will often form a\nnon-Gaussian distribution with power-law tails which are consistent with\nnonextensive statistics. As the exact shape of the distribution depends upon\nmany experimental parameters, it provides a potential new technique to directly\nmeasure them.", + "category": "nucl-ex" + }, + { + "text": "Direct observation of dijets in central Au+Au collisions at sqrt(s_NN) =\n 200 GeV: The STAR Collaboration at RHIC reports measurements of azimuthal correlations\nof high transverse momentum (p_T) charged hadrons in Au+Au collisions at higher\np_T than reported previously. As p_T is increased, a narrow, back-to-back peak\nemerges above the decreasing background, providing a clear dijet signal for all\ncollision centralities studied. Using these correlations, we perform a\nsystematic study of dijet production and suppression in nuclear collisions,\nproviding new constraints on the mechanisms underlying partonic energy loss in\ndense matter.", + "category": "nucl-ex" + }, + { + "text": "Shell Evolutions and Nuclear Forces: During the last 30 years, and more specifically during the last 10 years,\nmany experiments have been carried out worldwide using different techniques to\nstudy the shell evolution of nuclei far from stability. What seemed not\nconceivable some decades ago became rather common: all known magic numbers that\nare present in the valley of stability disappear far from stability and are\nreplaced by new ones at the drip line. By gathering selected experimental\nresults, beautifully consistent pictures emerge, that very likely take root in\nthe properties of the nuclear forces.The present manuscript describes some of\nthese discoveries and proposes an intuitive understanding of these shell\nevolutions derived from observations. Extrapolations to yet unstudied regions,\nas where the explosive r-process nucleosynthesis occurs, are proposed. Some\nremaining challenges and puzzling questions are also addressed.", + "category": "nucl-ex" + }, + { + "text": "The ALICE experiment -- A journey through QCD: The ALICE experiment was proposed in 1993, to study strongly interacting\nmatter at extreme energy densities via a comprehensive investigation of nuclear\ncollisions at the LHC. Its physics programme initially focused on the\ndetermination of the properties of the Quark-Gluon Plasma (QGP), a deconfined\nstate of quarks and gluons and was extended along the years, covering a diverse\nensemble of observables related to Quantum Chromodynamics (QCD), the theory of\nstrong interactions. The experiment has studied Pb-Pb, Xe-Xe, p-Pb and pp\ncollisions in the multi-TeV energy range, during the Run 1 and Run 2 data\ntaking periods at the LHC (2009-2018). The aim of this review article is to\ngather and summarise a selection of ALICE physics results and to discuss their\nimplications on the current understanding of the macroscopic and microscopic\nproperties of strongly interacting matter at the highest temperature reached in\nthe laboratory. It will be shown that it is possible to have a quantitative\ndescription of the properties of the QGP produced in Pb--Pb collisions. We also\nshow that various features, commonly ascribed to QGP formation, are detected\nfor a wide range of interacting system sizes. Precision measurements of\nQCD-related observables not directly connected to the study of the QGP will\nalso be discussed. Prospects for future measurements with the ALICE detector\nand its foreseen upgrades will also be briefly described.", + "category": "nucl-ex" + }, + { + "text": "Two-particle azimuthal correlations in photonuclear ultraperipheral\n Pb+Pb collisions at 5.02 TeV with ATLAS: Two-particle long-range azimuthal correlations are measured in photonuclear\ncollisions using 1.7 nb$^{-1}$ of 5.02 TeV Pb+Pb collision data collected by\nthe ATLAS experiment at the LHC. Candidate events are selected using a\ndedicated high-multiplicity photonuclear event trigger, a combination of\ninformation from the zero-degree calorimeters and forward calorimeters, and\nfrom pseudorapidity gaps constructed using calorimeter energy clusters and\ncharged-particle tracks. Distributions of event properties are compared between\ndata and Monte Carlo simulations of photonuclear processes. Two-particle\ncorrelation functions are formed using charged-particle tracks in the selected\nevents, and a template-fitting method is employed to subtract the non-flow\ncontribution to the correlation. Significant nonzero values of the second- and\nthird-order flow coefficients are observed and presented as a function of\ncharged-particle multiplicity and transverse momentum. The results are compared\nwith flow coefficients obtained in proton-proton and proton-lead collisions in\nsimilar multiplicity ranges, and with theoretical expectations. The unique\ninitial conditions present in this measurement provide a new way to probe the\norigin of the collective signatures previously observed only in hadronic\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "Peculiarities of isotopic temperatures obtained from p+A collisions at 1\n GeV: Nuclear temperatures obtained from inclusive measurements of double isotopic\nyield ratios of fragments produced in 1 GeV p + A collisions amount to about 4\nMeV nearly independent from the target mass.", + "category": "nucl-ex" + }, + { + "text": "Reexamination of phenomenological two-photon exchange corrections to the\n proton form factors and e+-p scattering: We extract the two-photon exchange (TPE) contributions to electron--proton\nelastic scattering using two parametrizations and compare the results to\ndifferent phenomenological extractions and direct calculations of the TPE\neffects. We find that many of the extractions give similar results, and\nhighlight the common assumptions and the impact of not including such\nassumptions. We provide a simple parametrization of the TPE contribution to the\nunpolarized cross section, along with an estimate of the fit uncertainties and\nthe uncertainties associated with the assumptions made in the extraction. We\nlook at the contributions as extracted from various e--p elastic scattering\nobservables, and make predictions for ratio $R^{e^{+} e^{-}}$ of\npositron-proton to electron-proton elastic scattering cross sections.", + "category": "nucl-ex" + }, + { + "text": "Photons and low-mass dileptons: results from PHENIX: Most recent PHENIX results on electromagnetic probes are presented including\nfirst preliminary results obtained with the Hadron Blind Detector (HBD) on e+e-\ninvariant mass spectra from Au+Au collisions at sqrt(s_NN) = 200 GeV.", + "category": "nucl-ex" + }, + { + "text": "LAMBDA: Large Area Modular BaF2 Detector Array for the measurement of\n high energy gamma rays: A large BaF2 detector array along with its dedicated CAMAC electronics and\nVME based data acquisition system has been designed, constructed and installed\nsuccessfully at VECC, Kolkata for studying high energy gamma rays (E>8 MeV).\nThe array consists of 162 detector elements. The detectors were fabricated from\nbare barium fluoride crystals (each measuring 35 cm in length and having\ncross-sectional area of 3.5 cm X 3.5 cm X 35.0 cm). The basic properties of the\ndetectors (energy resolution, time resolution, efficiency, uniformity, fast to\nslow ratio etc.) were studied exhaustively. Complete GEANT3 monte carlo\nsimulations were performed to optimize the detector design and also to generate\nthe response function. The detector system has been used successfully to\nmeasure high energy photons from 113Sb, formed by bombarding 145 and 160 MeV\n20Ne beams on a 93Nb target. The measured experimental spectra are in good\nagreement with those from a modified version of the statistical model code\nCASCADE. In this paper, we present the complete description of this detector\narray along with its in-beam performance.", + "category": "nucl-ex" + }, + { + "text": "Low-lying states in 8B: Excitation functions of elastic and inelastic 7Be+p scattering were measured\nin the energy range between 1.6 and 2.8 MeV in the c.m. An R-matrix analysis of\nthe excitation functions provides strong evidence for new positive parity\nstates in 8B. A new 2+ state at an excitation energy of 2.55 MeV was observed\nand a new 0+ state at 1.9 MeV is tentatively suggested. The R-matrix and Time\nDependent Continuum Shell Model were used in the analysis of the excitation\nfunctions. The new results are compared to the calculations of contemporary\ntheoretical models.", + "category": "nucl-ex" + }, + { + "text": "Study of Z production in PbPb and pp collisions at sqrt(s[NN]) = 2.76\n TeV in the dimuon and dielectron decay channels: The production of Z bosons is studied in the dimuon and dielectron decay\nchannels in PbPb and pp collisions at sqrt(s[NN]) = 2.76 TeV, using data\ncollected by the CMS experiment at the LHC. The PbPb data sample corresponds to\nan integrated luminosity of about 150 inverse microbarns, while the pp data\nsample collected in 2013 at the same nucleon-nucleon centre-of-mass energy has\nan integrated luminosity of 5.4 inverse picobarns. The Z boson yield is\nmeasured as a function of rapidity, transverse momentum, and collision\ncentrality. The ratio of PbPb to pp yields, scaled by the number of inelastic\nnucleon-nucleon collisions, is found to be 1.06 +/- 0.05 (stat) +/- 0.08 (syst)\nin the dimuon channel and 1.02 +/- 0.08 (stat) +/- 0.15 (syst) in the\ndielectron channel, for centrality-integrated Z boson production. This binary\ncollision scaling is seen to hold in the entire kinematic region studied, as\nexpected for a colourless probe that is unaffected by the hot and dense QCD\nmedium produced in heavy ion collisions.", + "category": "nucl-ex" + }, + { + "text": "The LHC as a Nucleus-Nucleus Collider: This paper begins with a summary of the status of the Large Hadron Collider\nat CERN, including the lead-ion injector chain and the plans for the first\nphases of commissioning and operation with colliding proton beams. In a later\nphase, the LHC will collide lead nuclei at centre-of-mass energies of 5.5 TeV\nper colliding nucleon pair. This leap to 28 times beyond what is presently\naccessible will open up a new regime, not only in the experimental study of\nnuclear matter, but also in the beam physics of hadron colliders.\nUltraperipheral and hadronic interactions of highly-charged beam nuclei will\ncause beam losses that dominate the luminosity decay and may quench\nsuperconducting magnets, setting upper limits on luminosity and stored beam\ncurrent. Lower limits are set by beam instrumentation. On the other hand,\ncoherent radiation by the nuclear charges should provide natural cooling to\novercome intra-beam scattering. As with protons, a flexible, staged approach to\nfull performance will test the limits and make optimal use of scheduled beam\ntime.", + "category": "nucl-ex" + }, + { + "text": "Strange Meson Enhancement in PbPb Collisions: The NA44 Collaboration has measured yields and differential distributions of\nK+, K-, pi+, pi- in transverse kinetic energy and rapidity, around the\ncenter-of-mass rapidity in 158 A GeV/c Pb+Pb collisions at the CERN SPS. A\nconsiderable enhancement of K+ production per pi is observed, as compared to\np+p collisions at this energy. To illustrate the importance of secondary hadron\nrescattering as an enhancement mechanism, we compare strangeness production at\nthe SPS and AGS with predictions of the transport model RQMD.", + "category": "nucl-ex" + }, + { + "text": "New data strengthen the connection between Short Range Correlations and\n the EMC effect: Recently published measurements of the two nucleon short range correlation\n($NN$-SRC) scaling factors, $a_2(A/d)$, strengthen the previously observed\ncorrelation between the magnitude of the EMC effect measured in electron deep\ninelastic scattering at $0.35\\le x_B\\le 0.7$ and the SRC scaling factor\nmeasured at $x_B \\ge 1$. The new results have improved precision and include\npreviously unmeasured nuclei. The measurements of $a_2(A/d)$ for $^9$Be and\n$^{197}$Au agree with published predictions based on the EMC-SRC correlation.\nThis paper examines the effects of the new data and of different corrections to\nthe data on the slope and quality of the EMC-SRC correlation, the size of the\nextracted deuteron IMC effect, and the free neutron structure function. The\nresults show that the linear EMC-SRC correlation is robust and that the slope\nof the correlation is insensitive to most combinations of corrections examined\nin this work. This strengthens the interpretation that both $NN$-SRC and the\nEMC effect are related to high momentum nucleons in the nucleus.", + "category": "nucl-ex" + }, + { + "text": "Evidence for Spinodal Decomposition in Nuclear Multifragmentation: Multifragmentation of a ``fused system'' was observed for central collisions\nbetween 32 MeV/nucleon 129Xe and natSn. Most of the resulting charged products\nwere well identified thanks to the high performances of the INDRA 4pi array.\nExperimental higher-order charge correlations for fragments show a weak but non\nambiguous enhancement of events with nearly equal-sized fragments. Supported by\ndynamical calculations in which spinodal decomposition is simulated, this\nobserved enhancement is interpreted as a ``fossil'' signal of spinodal\ninstabilities in finite nuclear systems.", + "category": "nucl-ex" + }, + { + "text": "Feasibility study of the quasi-free creation of the eta-prime meson in\n the reaction pn --> pn eta-prime: The feasibility of an investigation of the pn --> pn eta-prime reaction by\nmeans of the COSY-11 internal target facility is discussed. Appraisals are\nbased on the assumption of the quasi-free reactions of beam protons,\ncirculating in the cooler synchrotron COSY, with neutrons from a windowless\ndeuteron cluster target.", + "category": "nucl-ex" + }, + { + "text": "The study of heavy flavors via non-photonic electrons in STAR: The strong suppression of hadrons with high transverse momenta in central\nAu+Au collisions observed at RHIC is generally interpreted as a consequence of\nenergy loss of energetic partons in the hot and dense matter before\nfragmenting. The study of heavy quark production tests our understanding of\nenergy loss mechanisms.\n Heavy quarks were expected to lose less energy in the medium than light\nquarks and gluons due to the suppression of small-angle gluon radiation.\nHowever, the high transverse momentum non-photonic electron spectra, which are\ndominated by semi-leptonic decays of heavy quarks, show a strong suppression in\ncentral Au+Au collisions as well. Current theoretical models do not\nsatisfactory explain this observation.\n Preliminary non-photonic electron spectra are being extracted for Cu+Cu\ncollisions at $\\sqrt{s_{NN}}$ = 200 GeV. They are compared to the non-photonic\nelectron yields from p+p and Au+Au collisions at the same collision energy.\nThis provides a direct experimental test of the dependence of the non-photonic\nelectron yield on collision system size.", + "category": "nucl-ex" + }, + { + "text": "A precise measurement of the deuteron elastic structure function A(Q^2): The A(Q^2) structure function in elastic electron-deuteron scattering was\nmeasured at six momentum transfers Q^2 between 0.66 and 1.80 (GeV/c)^2 in Hall\nC at Jefferson Laboratory. The scattered electrons and recoil deuterons were\ndetected in coincidence, at a fixed deuteron angle of 60.5 degrees. These new\nprecise measurements resolve discrepancies between older sets of data. They put\nsignificant constraints on existing models of the deuteron electromagnetic\nstructure, and on the strength of isoscalar meson exchange currents.", + "category": "nucl-ex" + }, + { + "text": "Study of the gp-->etap reaction with the Crystal Ball detector at the\n Mainz Microtron(MAMI-C): The gp-->etap reaction has been measured with the Crystal Ball and TAPS\nmultiphoton spectrometers in the energy range from the production threshold of\n707 MeV to 1.4 GeV (1.49 =< W >= 1.87 GeV). Bremsstrahlung photons produced by\nthe 1.5-GeV electron beam of the Mainz Microtron MAMI-C and momentum analyzed\nby the Glasgow Tagging Spectrometer were used for the eta-meson production. Our\naccumulation of 3.8 x 10^6 gp-->etap-->3pi0p-->6gp events allows a detailed\nstudy of the reaction dynamics. The gp-->etap differential cross sections were\ndetermined for 120 energy bins and the full range of the production angles. Our\ndata show a dip near W = 1680 MeV in the total cross section caused by a\nsubstantial dip in eta production at forward angles. The data are compared to\npredictions of previous SAID and MAID partial-wave analyses and to thelatest\nSAID and MAID fits that have included our data.", + "category": "nucl-ex" + }, + { + "text": "The Importance of Correlations and Fluctuations on the Initial Source\n Eccentricity in High-Energy Nucleus-Nucleus Collisions: In this paper, we investigate various ways of defining the initial source\neccentricity using the Monte Carlo Glauber (MCG) approach. In particular, we\nexamine the participant eccentricity, which quantifies the eccentricity of the\ninitial source shape by the major axes of the ellipse formed by the interaction\npoints of the participating nucleons. We show that reasonable variation of the\ndensity parameters in the Glauber calculation, as well as variations in how\nmatter production is modeled, do not significantly modify the already\nestablished behavior of the participant eccentricity as a function of collision\ncentrality. Focusing on event-by-event fluctuations and correlations of the\ndistributions of participating nucleons we demonstrate that, depending on the\nachieved event-plane resolution, fluctuations in the elliptic flow magnitude\n$v_2$ lead to most measurements being sensitive to the root-mean-square, rather\nthan the mean of the $v_2$ distribution. Neglecting correlations among\nparticipants, we derive analytical expressions for the participant eccentricity\ncumulants as a function of the number of participating nucleons,\n$\\Npart$,keeping non-negligible contributions up to $\\ordof{1/\\Npart^3}$. We\nfind that the derived expressions yield the same results as obtained from\nmixed-event MCG calculations which remove the correlations stemming from the\nnuclear collision process. Most importantly, we conclude from the comparison\nwith MCG calculations that the fourth order participant eccentricity cumulant\ndoes not approach the spatial anisotropy obtained assuming a smooth nuclear\nmatter distribution. In particular, for the Cu+Cu system, these quantities\ndeviate from each other by almost a factor of two over a wide range in\ncentrality.", + "category": "nucl-ex" + }, + { + "text": "Charged jet cross sections and properties in proton-proton collisions at\n $\\sqrt{s}=7$ TeV: The differential charged jet cross sections, jet fragmentation distributions,\nand jet shapes are measured in minimum bias proton-proton collisions at\ncentre-of-mass energy $\\sqrt{s}=7$ TeV using the ALICE detector at the LHC.\nJets are reconstructed from charged particle momenta in the mid-rapidity region\nusing the sequential recombination $k_{\\rm T}$ and anti-$k_{\\rm T}$ as well as\nthe SISCone jet finding algorithms with several resolution parameters in the\nrange $R=0.2$ to $0.6$. Differential jet production cross sections measured\nwith the three jet finders are in agreement in the transverse momentum ($p_{\\rm\nT}$) interval $20$~$ 2.7\\times\n10^{24}~{\\rm yr}$ at 90%~C.L. Combining CUORE-0 data with the 19.75~kg$\\cdot$yr\nexposure of $^{130}$Te from the Cuoricino experiment we obtain $T^{0\\nu}_{1/2}\n> 4.0\\times 10^{24}~\\mathrm{yr}$ at 90%~C.L.~(Bayesian), the most stringent\nlimit to date on this half-life. Using a range of nuclear matrix element\nestimates we interpret this as a limit on the effective Majorana neutrino mass,\n$m_{\\beta\\beta}< 270$ -- $760~\\mathrm{meV}$.", + "category": "nucl-ex" + }, + { + "text": "First search for $2\\varepsilon$ and $\\varepsilon\u03b2^+$ decay of\n $^{174}$Hf: The first ever search for $2\\varepsilon$ and $\\varepsilon\\beta^+$ decay of\n$^{174}$Hf was realized using a high-pure sample of hafnium (with mass 179.8 g)\nand the ultra low-background HPGe-detector system located 225 m underground.\nAfter 75 days of data taking no indication of the double beta decay transitions\ncould be detected but lower limits for the half-lives of the different channels\nand modes of the decays were set on the level of $\\lim T_{1/2}\\sim\n10^{16}-10^{18}$ a.", + "category": "nucl-ex" + }, + { + "text": "\"$\\mathbf{{\\textit K^-}{\\textit p}{\\textit p}}$\", a\n ${\\overline{K}}$-Meson Nuclear Bound State, Observed in $^{3}{\\rm He}({K^-},\n \u039b p)n$ Reactions: We observed a distinct peak in the $\\Lambda p$ invariant mass spectrum of\n$^{3}{\\rm He}(K^-, \\, \\Lambda p)n$, well below the mass threshold of $m_K + 2\nm_p$. By selecting a relatively large momentum-transfer region $q = 350 \\sim\n650$ MeV/$c$, one can clearly separate the peak from the quasi-free process,\n$\\overline{K}N \\rightarrow \\overline{K}N$ followed by the non-resonant\nabsorption by the two spectator-nucleons $\\overline{K}NN \\rightarrow \\Lambda N\n$. We found that the simplest fit to the observed peak gives us a Breit-Wigner\npole position at $B_{\\rm {\\it Kpp}} = 47 \\pm 3 \\, (stat.) \\,^{+3}_{-6}\n\\,(sys.)$ MeV having a width $\\Gamma_{\\rm {\\it Kpp}} = 115 \\pm 7 \\, (stat.)\n\\,^{+10}_{-9} \\,(sys.)$ MeV, and the $S$-wave Gaussian reaction form-factor\nparameter $Q_{\\rm {\\it Kpp}} = 381 \\pm 14 \\, (stat.)\\,^{+57}_{-0} \\,(sys.)$\nMeV/$c$, as a new form of the nuclear bound system with strangeness --\n\"$K^-pp$\".", + "category": "nucl-ex" + }, + { + "text": "Improved Limit on Tensor Currents in the Weak Interaction from $^8$Li\n $\u03b2$ Decay: The electroweak interaction in the Standard Model (SM) is described by a pure\nvector-axial-vector structure, though any Lorentz-invariant component could\ncontribute. In this work, we present the most precise measurement of tensor\ncurrents in the low-energy regime by examining the $\\beta$-$\\bar{\\nu}$\ncorrelation of trapped $^{8}$Li ions with the Beta-decay Paul Trap. We find\n$a_{\\beta\\nu} = -0.3325 \\pm 0.0013_{stat} \\pm 0.0019_{syst}$ at $1\\sigma$ for\nthe case of coupling to right-handed neutrinos $(C_T=-C_T')$, which is\nconsistent with the SM prediction.", + "category": "nucl-ex" + }, + { + "text": "Machine studies for the development of storage cells at the ANKE\n facility of COSY: We present a measurement of the transverse intensity distributions of the\nCOSY proton beam at the target interaction point at ANKE at the injection\nenergy of 45 MeV, and after acceleration at 2.65 GeV. At 2.65 GeV, the machine\nacceptance was determined as well. From the intensity distributions the beam\nsize is determined, and together with the measured machine acceptance, the\ndimensions of a storage cell for the double-polarized experiments with the\npolarized internal gas target at the ANKE spectrometer are specified. An\noptimum storage cell for the ANKE experiments should have dimensions of 15mm x\n20mm x 390mm (vertical x horizontal x longitudinal), whereby a luminosity of\nabout 2.5*10^29 cm^-2*s^-1 with beams of 10^10 particles stored in COSY could\nbe reached.", + "category": "nucl-ex" + }, + { + "text": "Charged antiparticle to particle ratios near midrapidity in p+p\n collisions at sqrt(s_NN)=200 GeV: The ratios of the yields of primary charged antiparticles to particles have\nbeen obtained for pions, kaons, and protons near midrapidity for p+p collisions\nat sqrt(s_NN) = 200 GeV. Ratios of =1.000 +/- 0.012 (stat.) +/- 0.019\n(syst.), =0.93 +/- 0.05 (stat.) +/- 0.03 (syst.), and =0.85 +/-\n0.04 (stat.) +/- 0.03 (syst.) have been measured. The reported values represent\nthe ratio of the yields averaged over the rapidity range of 0.1 e+ nu, pi+ -> e+ nu gamma, pi+ -> pi0 e+ nu, and mu+ ->\ne+ nu nu-bar gamma. For the latter we report new preliminary values for the\nbranching ratio B(E_gamma >10 MeV, theta_(e-gamma) > 30deg) = 4.365 (9)_stat\n(42)_syst x 10^{-3}, and the decay parameter eta-bar = 0.006 (17)_stat\n(18)_syst, both in excellent agreement with standard model predictions. We\nreview recent measurements, particularly by the PIBETA and PEN experiments, and\nnear-term prospects for improvement. These and other similar precise low energy\nstudies complement modern collider results materially.", + "category": "nucl-ex" + }, + { + "text": "First Application of Pulse-Shape Analysis to Silicon Micro-Strip\n Detectors: The method of pulse-shape analysis (PSA) for particle identification (PID)\nwas applied to a double-sided silicon strip detector (DSSD) with a strip pitch\nof 300 \\{mu}m. We present the results of test measurements with particles from\nthe reactions of a 70 MeV 12C beam impinging on a mylar target. Good separation\nbetween protons and alpha particles down to 3 MeV has been obtained when\nexcluding the interstrip events of the DSSD from the analysis.", + "category": "nucl-ex" + }, + { + "text": "Searching for Jets in Heavy Ion Collisions: Jet quenching measurements using leading particles and their correlations\nsuffer from known biases, which can be removed via direct reconstruction of\njets in central heavy ion collisions. In this talk, we discuss several modern\njet reconstruction algorithms and background subtraction techniques that are\nappropriate to heavy ion collisions.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the $\u03bd_e$ and Total $^{8}$B Solar Neutrino Fluxes with\n the Sudbury Neutrino Observatory Phase-III Data Set: This paper details the solar neutrino analysis of the 385.17-day Phase-III\ndata set acquired by the Sudbury Neutrino Observatory (SNO). An array of $^3$He\nproportional counters was installed in the heavy-water target to measure\nprecisely the rate of neutrino-deuteron neutral-current interactions. This\ntechnique to determine the total active $^8$B solar neutrino flux was largely\nindependent of the methods employed in previous phases. The total flux of\nactive neutrinos was measured to be\n$5.54^{+0.33}_{-0.31}(stat.)^{+0.36}_{-0.34}(syst.)\\times 10^{6}$ cm$^{-2}$\ns$^{-1}$, consistent with previous measurements and standard solar models. A\nglobal analysis of solar and reactor neutrino mixing parameters yielded the\nbest-fit values of $\\Delta m^2 = 7.59^{+0.19}_{-0.21}\\times 10^{-5}{eV}^2$ and\n$\\theta = 34.4^{+1.3}_{-1.2}$ degrees.", + "category": "nucl-ex" + }, + { + "text": "Studies of nuclear equation of state with the HIRFL-CSR external-target\n experiment: The HIRFL-CSR external-target experiment (CEE) under construction is expected\nto provide novel opportunities to the studies of the thermodynamic properties,\nnamely the equation of state of nuclear matter (nEOS) with heavy ion collisions\nat a few hundreds MeV/u beam energies. Based on Geant 4 packages, the fast\nsimulations of the detector responses to the collision events generated using\ntransport model are conducted. The overall performance of CEE, including\nspatial resolution of hits, momentum resolution of tracks and particle\nidentification ability has been investigated. Various observables proposed to\nprobe the nEOS, such as the production of light clusters, $\\rm t/^3He$ yield\nratio, the radial flow, $\\pi^{-}/\\pi^{+}$ yield ratio and the neutral kaon\nyields, have been reconstructed. The feasibility of studying nEOS beyond the\nsaturation density via the aforementioned observables to be measured with CEE\nhas been demonstrated.", + "category": "nucl-ex" + }, + { + "text": "Suppression of soft nuclear bremsstrahlung in proton-nucleus collisions: Photon energy spectra up to the kinematic limit have been measured in 190 MeV\nproton reactions with light and heavy nuclei to investigate the influence of\nthe multiple-scattering process on the photon production. Relative to the\npredictions of models based on a quasi-free production mechanism a strong\nsuppression of bremsstrahlung is observed in the low-energy region of the\nphoton spectrum. We attribute this effect to the interference of photon\namplitudes due to multiple scattering of nucleons in the nuclear medium.", + "category": "nucl-ex" + }, + { + "text": "Bulk hadron production at high rapidities: Recent experimental observations on the `bulk' features of particle\nproduction at high (pseudo)rapidities will be reviewed. This kinematic region\nis of interest mostly because of its relevance to the theoretical description\nof initial state effects of nuclei at ultra-relativistic energies. Measurements\nof the charged hadron multiplicity density as well as the pseudorapidity\ndependence of the elliptic and directed flow exhibit a remarkable scaling\nproperty as a function of collision energy. This scaling seems to hold for\npions and even photons and J/Psi-s, but is violated for protons. The special\nrole of baryons will be discussed using selected results on nuclear\ntransparency and baryon stopping.", + "category": "nucl-ex" + }, + { + "text": "High-precision measurement of total fission cross sections in spallation\n reactions of 208Pb and 238U: Total cross sections for proton- and deuteron-induced-fission of 208Pb and\n238U have been determined in the energy range between 500 MeV and 1 GeV. The\nexperiment has been performed in inverse kinematics at GSI Darmstadt,\nfacilitating the counting of the projectiles and the identification of the\nreaction products. High precision between 5 and 7 percent has been achieved by\nindividually counting the beam particles and by registering both fission\nfragments in coincidence with high efficiency and full Z resolution. Fission\nwas clearly distinguished from other reaction channels. The results were found\nto deviate by up to 30 percent from Prokofiev's systematics on total fission\ncross sections. There is good agreement with an elaborate experiment performed\nin direct kinematics.", + "category": "nucl-ex" + }, + { + "text": "Centrality and pseudorapidity dependence of the charged-particle\n multiplicity density in Xe-Xe collisions at $\\sqrt{s_{\\rm NN}}$ = 5.44 TeV: In this Letter, the ALICE Collaboration presents the first measurements of\nthe charged-particle multiplicity density, $\\rm{d}N_{\\rm{ch}}/\\rm{d}\\eta$, and\ntotal charged-particle multiplicity, $N_{\\rm{ch}}^{\\rm{tot}}$, in Xe-Xe\ncollisions at a centre-of-mass energy per nucleon--nucleon pair of\n$\\sqrt{s_{\\rm NN}}$ = 5.44 TeV. The measurements are performed as a function of\ncollision centrality over a wide pseudorapidity range of $-3.5 < \\eta < 5$. The\nvalues of $\\rm{d}N_{\\rm{ch}}/\\rm{d}\\eta$ at mid-rapidity and\n$N_{\\rm{ch}}^{\\rm{tot}}$ for central collisions, normalised to the number of\nnucleons participating in the collision ($N_{\\rm{part}}$) as a function of\n$\\sqrt{s_{\\rm NN}}$, follow the trends established in previous heavy-ion\nmeasurements. The same quantities are also found to increase as a function of\n$N_{\\rm{part}}$, and up to the 5% most central collisions the trends are the\nsame as the ones observed in Pb-Pb at a similar energy. For more central\ncollisions, the Xe-Xe scaled multiplicities exceed those in Pb-Pb for a similar\n$N_{\\rm{part}}$. The results are compared to phenomenological models and\ntheoretical calculations based on different mechanisms for particle production\nin nuclear collisions. All considered models describe the data reasonably well\nwithin 15%.", + "category": "nucl-ex" + }, + { + "text": "$\u03c6$ meson production at forward rapidity in Pb-Pb collisions at\n $\\sqrt{s_\\mathrm{NN}}=2.76$ TeV: $\\phi$ meson measurements provide insight into strangeness production, which\nis one of the key observables for the hot medium formed in high-energy\nheavy-ion collisions. ALICE measured $\\phi$ production through its decay in\nmuon pairs in Pb-Pb collisions at $\\sqrt{s_\\mathrm{NN}}$ = 2.76 TeV in the\nintermediate transverse momentum range $2 < p_{\\rm T} < 5$ GeV/$c$ and in the\nrapidity interval $2.5pn eta reaction we determine the isospin I=0 component of\nthe total cross section for the NN-->NN eta reaction down to the threshold. We\nshow that the energy dependence of the total cross section ratios\n{\\sigma_{I=0}(pn-->pn eta)}/{\\sigma(pp-->pp eta)} and \\sigma_{I=0}(pn-->pn\neta)}/{\\sigma(pn-->d eta)} can be described using the Faldt and Wilkin\nanalitical parametrization of the nucleon-nucleon final state interaction.", + "category": "nucl-ex" + }, + { + "text": "Kaon Photoproduction and the $\u039b$ Decay Parameter $\u03b1_-$: The weak decay parameter $\\alpha_-$ of the $\\Lambda$ is an important quantity\nfor the extraction of polarization observables in various experiments.\nMoreover, in combination with $\\alpha_+$ from $\\bar\\Lambda$ decay it provides a\nmeasure for matter-antimatter asymmetry. The weak decay parameter also affects\nthe decay parameters of the $\\Xi$ and $\\Omega$ baryons and, in general, any\nquantity in which the polarization of the $\\Lambda$ is relevant. The recently\nreported value by the BESIII collaboration of $0.750(9)(4)$ is significantly\nlarger than the previous PDG value of $0.642(13)$ that had been accepted and\nused for over 40 years. In this work we make an independent estimate of\n$\\alpha_-$, using an extensive set of polarization data measured in kaon\nphotoproduction in the baryon resonance region and constraints set by spin\nalgebra. The obtained value is 0.721(6)(5). The result is corroborated by\nmultiple statistical tests as well as a modern phenomenological model, showing\nthat our new value yields the best description of the data in question. Our\nanalysis supports the new BESIII finding that $\\alpha_-$ is significantly\nlarger than the previous PDG value. Any experimental quantity relying on the\nvalue of $\\alpha_-$ should therefore be re-considered.", + "category": "nucl-ex" + }, + { + "text": "Rare $^{40}$K decay with implications for fundamental physics and\n geochronology: Potassium-40 is a widespread, naturally occurring isotope whose radioactivity\nimpacts subatomic rare-event searches, nuclear structure theory, and estimated\ngeological ages. A predicted electron-capture decay directly to the ground\nstate of argon-40 has never been observed. The KDK (potassium decay)\ncollaboration reports strong evidence of this rare decay mode. A blinded\nanalysis reveals a non-zero ratio of intensities of ground-state\nelectron-captures ($I_{\\text{EC}^0}$) over excited-state ones ($I_\\text{EC*}$)\nof $ I_{\\text{EC}^0} / I_\\text{EC*} = 0.0095 \\stackrel{\\text{stat}}{\\pm} 0.0022\n\\stackrel{\\text{sys}}{\\pm} 0.0010 $ (68% C.L.), with the null hypothesis\nrejected at 4$\\sigma$. In terms of branching ratio, this signal yields\n$I_{\\text{EC}^0} = 0.098\\% \\stackrel{\\text{stat}}{\\pm} 0.023\\%\n\\stackrel{\\text{sys}}{\\pm} 0.010\\% $, roughly half of the commonly used\nprediction, with consequences for various fields [L. Hariasz et al., companion\npaper, DOI: 10.1103/PhysRevC.108.014327].", + "category": "nucl-ex" + }, + { + "text": "Measurement of prompt D$^0$ meson azimuthal anisotropy in PbPb\n collisions at $\\sqrt{s_\\mathrm{NN}} = $5.02 TeV: The prompt D$^0$ meson azimuthal anisotropy coefficients, $v_2$ and $v_3$,\nare measured at midrapidity ($|y| < 1.0$) in PbPb collisions at a\ncenter-of-mass energy $\\sqrt{s_\\mathrm{NN}} = $5.02 TeV per nucleon pair with\ndata collected by the CMS experiment. The measurement is performed in the\ntransverse momentum ($p_\\mathrm{T}$) range of 1 to 40 GeV/c, for central and\nmidcentral collisions. The $v_2$ coefficient is found to be positive throughout\nthe $p_\\mathrm{T}$ range studied. The first measurement of the prompt D$^0$\nmeson $v_3$ coefficient is performed, and values up to 0.07 are observed for\n$p_\\mathrm{T}$ around 4 GeV/c. Compared to measurements of charged particles, a\nsimilar $p_\\mathrm{T}$ dependence, but smaller magnitude for $p_\\mathrm{T} < $6\nGeV/c, is found for prompt D$^0$ meson $v_2$ and $v_3$ coefficients. The\nresults are consistent with the presence of collective motion of charm quarks\nat low $p_\\mathrm{T}$ and a path length dependence of charm quark energy loss\nat high $p_\\mathrm{T}$, thereby providing new constraints on the theoretical\ndescription of the interactions between charm quarks and the quark-gluon\nplasma.", + "category": "nucl-ex" + }, + { + "text": "Results on flow from the ALICE Collaboration: This short overview includes recent results from the ALICE Collaboration on\nanisotropic flow of charged and identified particles in sqrt(sNN) = 2.76 TeV\nPb-Pb collisions. We also discuss charge dependent and event plane dependent\nazimuthal correlations that are important in tests of the chiral magnetic\neffect, as well as understanding the dynamics of the system evolution and\nhadronization process. Lastly, we present ALICE results obtained with a new\ntechnique, the event shape engineering, which allows to perform a physical\nanalysis on events with very large or small flow.", + "category": "nucl-ex" + }, + { + "text": "Competing quasifission and asymmetric fusion-fission in\n neutron-deficient sub-lead nuclei: To disentangle the role of shell effects and dynamics, fission fragment mass\ndistributions of $^{191}$Au, a nucleus in the newly identified island of mass\nasymmetric fission in the sub-lead region, have been measured down to\nexcitation energy of $\\approx$20 MeV above the fission barrier via two\ndifferent entrance channels, viz. $^{16}$O+$^{175}$Lu and $^{37}$Cl+$^{154}$Sm\nreactions. Apart from having signature of the shell effects in both the cases,\nclear experimental evidence of quasifission has been observed in the mass\ndistributions of the Cl induced reaction, that has also been substantiated by\nthe theoretical calculations. This crucial evidence along with a systematic\nanalysis of available experimental data has revealed that the dynamics in the\nentrance channel has significant influence on most of the reactions used\nearlier to explore the persistence of recently discovered mass asymmetry in\n$\\beta$-delayed fission at low energy in this mass region, ignoring which might\nlead to ambiguity in interpreting the heavy-ion data.", + "category": "nucl-ex" + }, + { + "text": "Influence of nuclear structure on sub-barrier hindrance in Ni+Ni fusion: Fusion-evaporation cross sections for $^{64}$Ni+$^{64}$Ni have been measured\ndown to the 10 nb level. For fusion between two open-shell nuclei, this is the\nfirst observation of a maximum in the $S$-factor, which signals a strong\nsub-barrier hindrance. A comparison with the $^{58}$Ni+$^{58}$Ni,\n$^{58}$Ni+$^{60}$Ni, and $^{58}$Ni+$^{64}$Ni systems indicates a strong\ndependence of the energy where the hindrance occurs on the stiffness of the\ninteracting nuclei.", + "category": "nucl-ex" + }, + { + "text": "Systematics of the low-energy electric dipole strength in the Sn\n isotopic chain: We present a systematic study of the mass dependence of the low-energy\nelectric dipole strength (LEDS) in Sn isotopes in the range $ A = 111 - 124$\nbased on data obtained with the Oslo method and with relativistic Coulomb\nexcitation in forward-angle ($p,p^\\prime$) scattering. The combined data cover\nan energy range of $2 - 20$ MeV which permits, with minimal assumptions, a\ndecomposition of the total strength into the contribution from the low-energy\ntail of the isovector giant dipole resonance (IVGDR) and possible\nresonance-like structures on top of it. In all cases, a resonance peaked at\nabout 8.3 MeV is observed, exhausting an approximately constant fraction of the\nThomas-Reiche-Kuhn (TRK) sum rule with a local maximum at $^{120}$Sn which\nmight be related to shell structure effects. For heavier isotopes ($A \\geq\n118$) a consistent description of the data requires the inclusion of a second\nresonance centered at 6.5 MeV, representing the isovector response of the pygmy\ndipole resonance (PDR). Its strength corresponds to a small fraction of the\ntotal LEDS only and shows an approximately linear dependence on mass number.\nThe experimental results are also compared to ab initio-based microscopic\ncalculations to investigate the importance of an inclusion of quasiparticle\nvibration coupling (qPVC) for a realistic description of the LEDS.", + "category": "nucl-ex" + }, + { + "text": "Jet splitting measurements in Pb--Pb and pp collisions at\n $\\sqrt{s}_{\\mathrm{NN}} =$ 5.02 TeV with ALICE: Recent ALICE measurements of jet splittings in Pb--Pb and pp collisions at\n$\\sqrt{s_{\\mathrm{NN}}}$ = 5.02 TeV are reported. These measurements scan the\nphase space of jet emissions in search of medium-induced signals which are\nexpected to emerge at different scales. These include effects such as multiple\nsoft-radiation, single hard emissions, and color coherence. The Lund plane\ndiagram is shown, including projections onto distributions of the splitting\nscale $k_{\\mathrm{T}}$ in intervals of the splitting angle $R_{\\mathrm{g}}$.\nSoft Drop grooming is applied to access hard splittings within the jet,\nenabling measurements of groomed substructure variables. These include the\nshared momentum fraction $z_{\\mathrm{g}}$ between the two hardest subjets and\nthe number of Soft Drop splittings $n_{\\mathrm{SD}}$. The results in Pb--Pb\ncollisions are compared to PYTHIA events embedded into a Pb--Pb background to\nseparate out background from in-medium effects. Measurements of\n$z_{\\mathrm{g}}$ and the normalized splitting angle $\\theta_{\\mathrm{g}}$ will\nalso be shown in pp collisions at $\\sqrt{s}$ = 5.02 TeV for different grooming\nsettings.", + "category": "nucl-ex" + }, + { + "text": "Comment on \"Fission Mass Widths in $^{19}$F + $^{232}$Th, $^{16}$O +\n $^{235,238}$ U reactions at near barrier energies: A critical re-analysis of the experimental data to reject transfer fission\ncomponent did not change the fragment mass widths and hence the conclusion\nregarding abrupt rise in mass widths with decreasing energy around Coulomb\nbarrier remains unchanged", + "category": "nucl-ex" + }, + { + "text": "Characteristics of Parton Energy Loss Studied with High-p_T Particle\n Spectra from PHENIX: In the first three years of the physics program at the Relativistic Heavy Ion\nCollider (RHIC) a picture was established in which the suppression of hadrons\nat high transverse momenta (p_T) in central Au+Au collisions is explained by\nenergy loss of quark and gluon jets in a medium of high color-charge density.\nMeasurements of single particle spectra for a smaller nucleus (Cu), for\ndifferent center-of-mass energies and with higher statistics were performed in\nthe subsequent years and are used to test predictions and assumptions of jet\nquenching models in more detail. The measurements presented here are consistent\nwith a parton energy loss scenario so that these models can be used to relate\nthe observed suppression to properties of the created medium.", + "category": "nucl-ex" + }, + { + "text": "Isospin Character of the Pygmy Dipole Resonance in 124Sn: The pygmy dipole resonance has been studied in the proton-magic nucleus 124Sn\nwith the (a,a'g) coincidence method at E=136 MeV. The comparison with results\nof photon-scattering experiments reveals a splitting into two components with\ndifferent structure: one group of states which is excited in (a,a'g) as well as\nin (g,g') reactions and a group of states at higher energies which is only\nexcited in (g,g') reactions. Calculations with the self-consistent relativistic\nquasiparticle time-blocking approximation and the quasiparticle phonon model\nare in qualitative agreement with the experimental results and predict a\nlow-lying isoscalar component dominated by neutron-skin oscillations and a\nhigher-lying more isovector component on the tail of the giant dipole\nresonance.", + "category": "nucl-ex" + }, + { + "text": "Closing in on critical net-baryon fluctuations at LHC energies:\n cumulants up to third order in Pb$-$Pb collisions: Fluctuation measurements are important sources of information on the\nmechanism of particle production at LHC energies. This article reports the\nfirst experimental results on third-order cumulants of the net-proton\ndistributions in Pb$-$Pb collisions at a center-of-mass energy $\\sqrt{s_{\\rm\nNN}} = 5.02$ TeV recorded by the ALICE detector. The results on the\nsecond-order cumulants of net-proton distributions at $\\sqrt{s_{\\rm NN}} =\n2.76$ and $5.02$ TeV are also discussed in view of effects due to the global\nand local baryon number conservation. The results demonstrate the presence of\nlong-range rapidity correlations between protons and antiprotons. Such\ncorrelations originate from the early phase of the collision. The experimental\nresults are compared with HIJING and EPOS model calculations, and the\ndependence of the fluctuation measurements on the phase-space coverage is\nexamined in the context of lattice quantum chromodynamics (LQCD) and hadron\nresonance gas (HRG) model estimations. The measured third-order cumulants are\nconsistent with zero within experimental uncertainties of about 4% and are\ndescribed well by LQCD and HRG predictions.", + "category": "nucl-ex" + }, + { + "text": "Dielectron Production in Heavy Ion Collisions at 158 GeV/c per Nucleon: In this paper, the low-mass electron pair production in 158 AGeV/c Pb-Au\ncollisions is investigated with the Cherenkov Ring Electron Spectrometer\n(CERES) at the Super Proton Synchrotron accelerator (SPS) at CERN. The main\ngoal is to search for modifications of hadron properties in hot and dense\nnuclear matter. The presented re-analysis of the 1996 data set is focused on a\ndetailed study of the combinatorial-background subtraction by means of the\nmixed-event technique. The results confirm previous findings of CERES. The\ndielectron production in the mass range of 0.25$ is an order\nparameter. For higher temperature or higher matter-density, $|<\\bar{q}q>|$\ndecreases reflecting the restoration of the symmetry. In contrast to these\nclear-cut arguments, experimental evidence is so far limited. First of all, the\n$\\bar{q}q$ is nothing but the vacuum itself. It is neither visible nor\nperceptible. In this article, we unravel this invisible existence by high\nprecision measurement of pionic atoms, $\\pi^-$-meson-nucleus bound systems.\nUsing the $\\pi^-$ as a probe, we demonstrate that $|<\\bar{q}q>|$ is reduced in\nthe nucleus at 58% of the normal nuclear density by a factor of 77 $\\pm$ 2%\ncompared with that in the vacuum. This reduction indicates that the chiral\nsymmetry is partially restored due to the extremely high density of the\nnucleus. The present experimental result clearly exhibits the existence of the\nhidden structure, the chiral condensate, in the vacuum.", + "category": "nucl-ex" + }, + { + "text": "Performance of the ALICE VZERO system: ALICE is an LHC experiment devoted to the study of strongly interacting\nmatter in proton-proton, proton--nucleus and nucleus-nucleus collisions at\nultra-relativistic energies. The ALICE VZERO system, made of two scintillator\narrays at asymmetric positions, one on each side of the interaction point,\nplays a central role in ALICE. In addition to its core function as a trigger,\nthe VZERO system is used to monitor LHC beam conditions, to reject beam-induced\nbackgrounds and to measure basic physics quantities such as luminosity,\nparticle multiplicity, centrality and event plane direction in nucleus-nucleus\ncollisions. After describing the VZERO system, this publication presents its\nperformance over more than four years of operation at the LHC.", + "category": "nucl-ex" + }, + { + "text": "Superdeformation in Asymmetric N$>$Z Nucleus $^{40}$Ar: A rotational band with five $\\gamma$-ray transitions ranging from 2$^{+}$ to\n12$^{+}$ states was identified in $^{40}$Ar. This band is linked through\n$\\gamma$ transitions from the excited 2$^{+}$, 4$^{+}$ and 6$^{+}$ levels to\nthe low-lying states; this determines the excitation energy and the spin-parity\nof the band. The deduced transition quadrupole moment of 1.45$^{+0.49}_{-0.31}\neb$ indicates that the band has a superdeformed shape. The nature of the band\nis revealed by cranked Hartree--Fock--Bogoliubov calculations and a\nmultiparticle--multihole configuration is assigned to the band.", + "category": "nucl-ex" + }, + { + "text": "Reference cross section measurements with ALICE in pp and Pb-Pb\n collisions at LHC: Cross sections of reference trigger processes were obtained based on beam\nproperty measurements in dedicated luminosity calibration experiments (van der\nMeer scans). These cross-sections are essential for absolute cross section\ndeterminations of physics processes. The reference cross sections are presented\nfor pp collisions at two center of mass energies; 2.76 TeV and 7 TeV, and for\nPb-Pb collisions at 2.76 TeV together with a discussion of the systematic\nuncertainty originating from beam intensity and rate measurement uncertainties.", + "category": "nucl-ex" + }, + { + "text": "K*(892)^0 production in p+p interactions at 158 GeV/c from NA61/SHINE: The measurement of $K^{*}(892)^0$ resonance production via its $K^{+}\\pi^{-}$\ndecay mode in inelastic p+p collisions at beam momentum 158~GeV/c\n($\\sqrt{s_{NN}}=17.3$~GeV) is presented. The data were recorded by the\nNA61/SHINE hadron spectrometer at the CERN Super Proton Synchrotron. The first\never double differential measurements and $p_T$-integrated spectra of\n$K^{*}(892)^0$ at beam momenta of 158 GeV/c was done by using the\n\\textit{template} fitting method. The full phase-space yields, mass and width\nof $K^{*}(892)^0$ mesons are compared with Hadron Resonance Gas models as well\nas with world data on p+p and nucleus-nucleus collisions.", + "category": "nucl-ex" + }, + { + "text": "Discovery of the astatine, radon, francium, and radium isotopes: Currently, thirty-nine astatine, thirty-nine radon, thirty-five francium, and\nthirty-four radium isotopes have so far been observed; the discovery of these\nisotopes is discussed. For each isotope a brief summary of the first refereed\npublication, including the production and identification method, is presented.", + "category": "nucl-ex" + }, + { + "text": "Measurements using a prototype array of plastic scintillator bars for\n reactor based electron anti-neutrino detection: We report measurement of reactor based electron anti-neutrinos from a\nprototype array of plastic scintillator bars ( mini-ISMRAN ) located inside\nDhruva research reactor hall, BARC. The detector setup took data for 128 days\nfor reactor on (RON) and 51 days for reactor off (ROFF) condition. A detailed\nanalysis procedure is developed to select the anti-neutrino candidate events\nbased on the energy deposition, number of bars hit as well as topological event\nselection criteria in position and time. Each of these selection criteria are\ncompared with Monte Carlo based simulations and further an embedding technique\nis used to estimate the efficiencies from a data driven background study. The\nobtained anti-neutrino like events in RON condition are 218 $\\pm$ 50 (stat)\n$\\pm$ 37 (sys) after background subtraction. The obtained results are compared\nwith theoretical estimation which yields 214 $\\pm$ 32 (sys) anti-neutrino\nevents for the RON condition.", + "category": "nucl-ex" + }, + { + "text": "Basic characterization of highly enriched uranium by gamma spectrometry: Gamma-spectrometric methods suitable for the characterization of highly\nenriched uranium samples encountered in illicit trafficking of nuclear\nmaterials are presented. In particular, procedures for determining the 234U,\n235U, 238U, 232U and 236U contents and the age of highly enriched uranium are\ndescribed. Consequently, the total uranium content and isotopic composition can\nbe calculated. For determining the 238U and 232U contents a low background\nchamber was used. In addition, age dating of uranium was also performed using\nlow-background spectrometry.", + "category": "nucl-ex" + }, + { + "text": "PHENIX photons and dileptons: Electro-magnetic probes such as dileptons and photons are strong probes to\ninvestigate the thermodynamical state of the early stages of collisions since\nthey leave the system unscathed. The PHENIX experiment has measured both\nphotons and dileptons in p+p, d+Au and Au+Au collisions. An excess of dilepton\nyield over the expected hadronic contribution is seen in 0.2-0.8\\,GeV/$c^2$ in\nAu+Au collisions, which is prominent in lower $p_T$ and most central. Direct\nphotons are measured through their internal conversion to electron pairs. We\nsaw a large enhancement in Au+Au collisions over p+p yield scaled by the number\nof binary collisions. It turned out from the latest results on d+Au collisions\nthat this enhancement is not explainable by a nuclear effect.", + "category": "nucl-ex" + }, + { + "text": "Direct observation of the dead-cone effect in QCD: In particle collider experiments, elementary particle interactions with large\nmomentum transfer produce quarks and gluons (known as partons) whose evolution\nis governed by the strong force, as described by the theory of quantum\nchromodynamics (QCD). These partons subsequently emit further partons in a\nprocess that can be described as a parton shower which culminates in the\nformation of detectable hadrons. Studying the pattern of the parton shower is\none of the key experimental tools for testing QCD. This pattern is expected to\ndepend on the mass of the initiating parton, through a phenomenon known as the\ndead-cone effect, which predicts a suppression of the gluon spectrum emitted by\na heavy quark of mass $m_{\\rm{Q}}$ and energy $E$, within a cone of angular\nsize $m_{\\rm{Q}}$/$E$ around the emitter. Previously, a direct observation of\nthe dead-cone effect in QCD had not been possible, owing to the challenge of\nreconstructing the cascading quarks and gluons from the experimentally\naccessible hadrons. We report the direct observation of the QCD dead cone by\nusing new iterative declustering techniques to reconstruct the parton shower of\ncharm quarks. This result confirms a fundamental feature of QCD. Furthermore,\nthe measurement of a dead-cone angle constitutes a direct experimental\nobservation of the non-zero mass of the charm quark, which is a fundamental\nconstant in the standard model of particle physics.", + "category": "nucl-ex" + }, + { + "text": "Determination of Critical Exponents in Nuclear Systems: Signatures of critical behaviour in nuclear fragmentation are often based on\narguments from percolation theory. We demonstrate with general thermodynamic\nconsiderations and studies of the Ising model that the reliance on percolation\nas a reference model bears the risk of missing parts of the essential physics.", + "category": "nucl-ex" + }, + { + "text": "Latest results from the PHOBOS experiment: Over the past years PHOBOS has continued to analyze the large datasets\nobtained from the first five runs of the Relativistic Heavy Ion Collider (RHIC)\nat Brookhaven National Laboratory. The two main analysis streams have been\npursued. The first one aims to obtain a broad and systematic survey of global\nproperties of particle production in heavy ion collisions. The second class\nincludes the study of fluctuations and correlations in particle production.\nBoth type of studies have been performed for a variety of the collision\nsystems, covering a wide range in collision energy and centrality. The uniquely\nlarge angular coverage of the PHOBOS detector and its ability to measure\ncharged particles down to very low transverse momentum is exploited. The latest\nphysics results from PHOBOS, as presented at Quark Matter 2008 Conference, are\ncontained in this report.", + "category": "nucl-ex" + }, + { + "text": "Comments on the \"Reply to 'Comment on \"Piezonuclear decay of thorium\"\n [Phys. Lett. A 373 (2009) 1956]' [Phys. Lett. A (2009, in press]\" [Phys.\n Lett. A (2009), in press] by F. Cardone et. al: In a recent article F. Cardone et al. [Phys. Lett. A 373 (2009) 1956] have\nclaimed that subjecting a solution of 228Th to cavitation leads to a\n\"transformation\" of the thorium nuclei that is 104 times faster than the normal\nnuclear decay for this isotope. We have criticized the evidence provided for\nthis claim in a \"Comment\" [Phys. Lett. A (2009), in press, DOI\n10.1016/j.physleta.2009.08.045]. In their \"Reply\" [Phys. Lett. A (2009), in\npress, DOI 10.1016/j.physleta.2009.08.047] Cardone et al. answer only some\nminor points but avoid addressing the real issue. They even state a new\nextraordinary claim, namely that the thorium \"transformations\" occur without\nemission of gamma rays. In addition, the information provided in their Reply\ndisplays a worrying lack of control of their experimental situation and the\ndata they put forward as evidence for their claims. We point out several\nshortcomings and errors in the described experimental preparations, set-up and\nreporting, as well as in the data analysis. We conclude that the evidence\npresented by Cardone et al. is insufficient to justify their claims and that\nthe shortcomings of their work are so severe that the original paper and the\nReply should be withdrawn.", + "category": "nucl-ex" + }, + { + "text": "Transverse Single-Spin Asymmetry for Inclusive and Diffractive\n Electromagnetic Jets at Forward Rapidity in $p^{\\uparrow}$+p Collisions at\n $\\sqrt{s} = 200$ GeV and $510$ GeV at STAR: There have been numerous attempts, in the last decades, to understand the\norigin of the unexpectedly large transverse single-spin asymmetry ($A_{N}$)\nobserved in inclusive hadron productions at forward rapidities in transversely\npolarized $p^{\\uparrow}$+$p$ collisions at different center-of-mass energies\n($\\sqrt{s}$). The current theoretical frameworks aimed at explaining this\npuzzle include the twist-3 contributions in the collinear factorization\nframework, as well as the transverse-momentum-dependent contributions from the\ninitial-state quark and gluon Sivers functions, and/or final-state Collins\nfragmentation functions. Besides, there are indications that the diffractive\nprocesses may contribute to the large $A_{N}$. We present the detailed\ninvestigations into the $A_{N}$ for electromagnetic jets (EM-jets) produced in\ninclusive processes using the Forward Meson Spectrometer with transversely\npolarized $p^{\\uparrow}$+ $p$ data at $\\sqrt{s} =$ 200 GeV collected in 2015 at\nSTAR. We observe a negative value for the $A_{N}$ of EM-jets in diffractive\nprocesses. This finding shows a different sign for $A_{N}$ in inclusive\nprocesses and needs further theoretical input in order to be understood.\nFinally, we present the statistical projections of the $A_{N}$ for inclusive\nand diffractive EM-jets utilizing $p^{\\uparrow}$+ $p$ data at $\\sqrt{s} =$ 510\nGeV collected in 2017 at STAR. This dataset allows for a substantial\nenhancement in statistical precision.", + "category": "nucl-ex" + }, + { + "text": "Discovery of palladium, antimony, tellurium, iodine, and xenon isotopes: Currently, thirty-eight palladium, thirty-eight antimony, thirty-nine\ntellurium, thirty-eight iodine, and forty xenon isotopes have been observed and\nthe discovery of these isotopes is discussed here. For each isotope a brief\nsynopsis of the first refereed publication, including the production and\nidentification method, is presented.", + "category": "nucl-ex" + }, + { + "text": "Accessing weak neutral-current coupling $g_{AA}^{eq}$ using positron and\n electron beams at Jefferson Lab: Low-energy neutral-current couplings arising in the Standard Model of\nelectroweak interactions can be constrained in lepton scattering off hydrogen\nor a nuclear fixed target. Recent polarized electron scattering experiments at\nJefferson Lab (JLab) have improved the precision in the parity-violating types\nof effective couplings. On the other hand, the only known way to access the\nparity-conserving counterparts is to compare scattering cross sections between\na lepton and an anti-lepton beam. We review the current knowledge of both types\nof couplings and how to constrain them. We also present exploratory\ncalculations for a possible measurement of $g_{AA}^{eq}$ using the planned\nSoLID spectrometer combined with a possible positron beam at JLab.", + "category": "nucl-ex" + }, + { + "text": "Photoproduction of low-$p_{\\rm T}$ J/$\u03c8$ from peripheral to central\n Pb$-$Pb collisions at 5.02 TeV: An excess of J/$\\psi$ yield at very low transverse momentum ($p_{\\rm T} <\n0.3$ GeV/$c$), originating from coherent photoproduction, is observed in\nperipheral and semicentral hadronic Pb$-$Pb collisions at a center-of-mass\nenergy per nucleon pair of $\\sqrt{s_{\\rm NN}} = 5.02$ TeV. The measurement is\nperformed with the ALICE detector via the dimuon decay channel at forward\nrapidity ($2.5 np scattering amplitude in the backward\ndirection with few ambiguities.", + "category": "nucl-ex" + }, + { + "text": "Isotopic distribution of fission fragments in collisions between 238U\n beam and 9Be and 12C targets at 24 MeV/u: Inverse kinematics coupled to a high-resolution spectrometer is used to\ninvestigate the isotopic yields of fission fragments produced in reactions\nbetween a 238U beam at 24 MeV/u and 9Be and 12C targets. Mass, atomic number\nand isotopic distributions are reported for the two reactions. These\ninformations give access to the neutron excess and the isotopic distribution\nwidths, which together with the atomic-number and mass distributions are used\nto investigate the fusion-fission dynamics.", + "category": "nucl-ex" + }, + { + "text": "Recent results on femtoscopic correlations with the CMS experiment: The study of femtoscopic correlations in high-energy collisions is a powerful\ntool to investigate the space-time structure of the particle emitting region\nformed in such collisions, as well as to probe interactions that the involved\nparticles may undergo after being emitted. An overview of the recent results\nfrom the CMS experiment at the LHC on the two-particle femtoscopic correlations\nmeasurements using charged particles and identified hadrons in pp and PbPb\ncollisions is presented. In general, the femtoscopic parameters are obtained\nassuming a Gaussian or an exponential shape to describe the emitting source\ndistribution. In some cases, however, the generalized Gaussian, i.e., the\nsymmetric alpha-stable L\\'evy distribution, is favored to describe the source.\nSome of the measurements allow to extract the parameters of the strong\ninteraction felt by hadrons using their femtoscopic correlations. The studies\nare performed in a wide range of the pair average transverse momentum (or\naverage transverse mass) and charged particle multiplicities. In addition,\nprospects for future physics results using the CMS experiment are also\ndiscussed.", + "category": "nucl-ex" + }, + { + "text": "An improved method to access initial states in relativistic heavy-ion\n collisions: Observables in heavy-ion collisions are generally categorized into\ncentralities, which reflect an average over events within a range of impact\nparameter including a wide variety of initial state configurations. A multiple\nbinning method using spectator neutrons within each centrality has been\npreviously shown to provide access to events with rare initial state\nconditions. This work suggests an improvement in quantifying the difference\nbetween standard centrality and spectator neutron binning towards accessing the\ninitial state properties. A selection of events with higher initial state\ndensity at fixed participating nucleon number was observed to result in larger\nfinal state particle production and smaller elliptic flow. The relative\ndifference between observables in centrality and spectator binning shows\nreduced sensitivity for the observables dominated by impact parameter\nfluctuations in initial state such as triangular flow. This property makes the\nspectator binning method a good candidate to separate geometric contributions\nfrom random fluctuations in initial state towards final state observables.", + "category": "nucl-ex" + }, + { + "text": "Flow dominance and factorization of transverse momentum correlations in\n Pb-Pb collisions at the LHC: We present the first measurement of the two-particle transverse momentum\ndifferential correlation function, $P_2\\equiv\\langle \\Delta p_{\\rm T} \\Delta\np_{\\rm T} \\rangle /\\langle p_{\\rm T} \\rangle^2$, in Pb-Pb collisions at\n$\\sqrt{s_{_{\\rm NN}}} =$ 2.76 TeV. Results for $P_2$ are reported as a function\nof relative pseudorapidity ($\\Delta \\eta$) and azimuthal angle ($\\Delta\n\\varphi$) between two particles for different collision centralities. The\n$\\Delta \\phi$ dependence is found to be largely independent of $\\Delta \\eta$\nfor $|\\Delta \\eta| \\geq$ 0.9. In 5% most central Pb-Pb collisions, the\ntwo-particle transverse momentum correlation function exhibits a clear\ndouble-hump structure around $\\Delta \\varphi = \\pi$ (i.e., on the away side),\nwhich is not observed in number correlations in the same centrality range, and\nthus provides an indication of the dominance of triangular flow in this\ncollision centrality. Fourier decompositions of $P_2$, studied as a function of\ncollision centrality, show that correlations at $|\\Delta \\eta| \\geq$ 0.9 can be\nwell reproduced by a flow ansatz based on the notion that measured momentum\ncorrelations are strictly determined by the collective motion of the system.", + "category": "nucl-ex" + }, + { + "text": "Rescattering effects on resonances production in small systems with\n ALICE at the LHC: Recent multiplicity-dependent analyses of pp and p--Pb collision data have\nrevealed that particle production shares similar features with that in\nheavy-ion collisions. Studies using resonances could help to understand the\npossible onset of collective-like phenomena and the presence of a hadronic\nphase in small collision systems. Measurements of the differential yields of\nresonances with different lifetime, mass, quark content, and quantum numbers\ncould enable understanding the mechanisms that influence the shape of particle\nmomentum spectra, lifetime of the hadronic phase, strangeness production,\nparton energy loss, and collective effects. New ALICE results on various\nhadronic resonances in small collision systems at Large Hadron Collider (LHC)\nenergies, including the multiplicity dependence measurements of $\\Lambda$(1520)\nand K$^*$(892)$^{\\pm}$ and the production of $\\phi$-meson pairs are presented\nhere. Results will be also compared with model calculations.", + "category": "nucl-ex" + }, + { + "text": "One-neutron knockout reaction of 17C on a hydrogen target at 70\n MeV/nucleon: First experimental evidence of the population of the first 2- state in 16C\nabove the neutron threshold is obtained by neutron knockout from 17C on a\nhydrogen target. The invariant mass method combined with in-beam gamma-ray\ndetection is used to locate the state at 5.45(1) MeV. Comparison of its\npopulating cross section and parallel momentum distribution with a Glauber\nmodel calculation utilizing the shell-model spectroscopic factor confirms the\ncore-neutron removal nature of this state. Additionally, a previously known\nunbound state at 6.11 MeV and a new state at 6.28(2) MeV are observed. The\nposition of the first 2- state, which belongs to a member of the lowest-lying\np-sd cross shell transition, is reasonably well described by the shell-model\ncalculation using the WBT interaction.", + "category": "nucl-ex" + }, + { + "text": "Beta decays in investigations and searches for rare effects: Current status of experimental investigations of rare single beta decays\n(48Ca, 50V, 96Zr, 113Cd, 113mCd, 115In, 123Te, 180mTa, 222Rn) is reviewed.\nNuclei which decay through single beta decay very often constitute backgrounds\nin studies of rare effects like double beta decay, solar neutrinos or dark\nmatter. Summary of correction factors used in description of forbidden beta\ndecays is also briefly given.", + "category": "nucl-ex" + }, + { + "text": "Multiplicity distribution and spectra of negatively charged hadrons in\n Au+Au collisions at sqrt(s_nn) = 130 GeV: The minimum bias multiplicity distribution and the transverse momentum and\npseudorapidity distributions for central collisions have been measured for\nnegative hadrons (h-) in Au+Au interactions at sqrt(s_nn) = 130 GeV. The\nmultiplicity density at midrapidity for the 5% most central interactions is\ndNh-/deta|_{eta = 0} = 280 +- 1(stat)+- 20(syst), an increase per participant\nof 38% relative to ppbar collisions at the same energy. The mean transverse\nmomentum is 0.508 +- 0.012 GeV/c and is larger than in central Pb+Pb collisions\nat lower energies. The scaling of the h- yield per participant is a strong\nfunction of pt. The pseudorapidity distribution is almost constant within\n|eta|<1.", + "category": "nucl-ex" + }, + { + "text": "Symmetry energy dependence of long timescale isospin transport: Isospin transport occurring within dinuclear projectile-like fragments (PLFs)\nproduced in heavy- ion collisions is explored as a probe of the nuclear\nsymmetry energy. Within the framework of the Constrained Molecular Dynamics\nmodel (CoMD), the existence of the long-lived dinuclear PLFs, for up to 800\nfm/c, is observed. It is demonstrated that changes in the of the two\nfragments resulting from the breakup of the dinuclear PLF is due to isospin\ntransport. The rate of the transport between the two fragments is shown to be\ndependent on the slope of the symmetry energy at saturation density. Comparison\nof the CoMD calculations with experimental data establish that the evolution of\n could be used to constrain the density dependence of the symmetry energy.", + "category": "nucl-ex" + }, + { + "text": "Methods for the Study of Particle Production Fluctuations: We discuss various measures of net charge (conserved quantities) fluctuations\nproposed for the identification of critical phenomena in heavy ion collisions.\nWe show the dynamical component of fluctuations of the net charge can be\nexpressed simply in terms of integrals of two- and single-particle densities.\nWe discuss the dependence of the fluctuation observables on detector\nacceptance, detection efficiency and colliding system size and collision\ncentrality. Finally, we present a toy model of particle production including\ncharge conservation and resonance production to gauge the effects of such\nresonances and finite acceptance on the net charge fluctuations.", + "category": "nucl-ex" + }, + { + "text": "The pp -> pp pi pi pi reaction channels in the threshold region: The cross section for prompt neutral and charged three pion production in pp\ninteractions was measured at excess energies in the range 160 - 217 MeV. That\ncomprises the first measurement of the pp->pp pi0pi0pi0 reaction and the\ncomparison with the pp->pp pi+pi-pi0 reaction, in a very direct way. The\nexperiment was performed above the eta meson production threshold and the cross\nsection normalization was obtained from a concurrent measurement of the\nreaction pp->pp eta with the eta decaying into 3 pions. Since the same final\nstates are selected, the measurement has a low systematical error. The measured\ncross section ratio sigma(pp->pp pi+pi-pi0)/sigma(pp->pp pi0\\pi0\\pi0) is\ncompared to predictions of dominance of different isobars in the intermediate\nstate.", + "category": "nucl-ex" + }, + { + "text": "$J/\u03c8$ production in PHENIX: Heavy quarkonia production is expected to be sensitive to the formation of a\nquark gluon plasma (QGP). The PHENIX experiment has measured $J/\\psi$\nproduction at $\\sqrt{s_{NN}}=$~200 GeV in Au+Au and Cu+Cu collisions, as well\nas in reference p+p and d+Au runs. $J/\\psi$'s were measured both at mid\n($|y|<0.35$) and forward ($1.2<|y|<2.2$) rapidity. In this letter, we present\nthe A+A preliminary results and compare them to normal cold nuclear matter\nexpectations derived from PHENIX d+Au and p+p measurements as well as to\ntheoretical models including various effects (color screening, recombination,\nsequential melting...).", + "category": "nucl-ex" + }, + { + "text": "The Halo of 14Be: The two-neutron halo nucleus 14Be has been investigated in a kinematically\ncomplete measurement of the fragments (12Be and neutrons) produced in\ndissociation at 35 MeV/nucleon on C and Pb targets. Two-neutron removal\ncross-sections, neutron angular distributions and invariant mass spectra\ncharacteristic of a halo were observed and the electromagnetic (EMD)\ncontributions deduced. Comparison with three-body model predictions indicate\nthat the halo wavefunction contains a large 2s1/2^2 admixture. The EMD\ninvariant mass spectrum exhibited a relatively narrow structure near threshold\n(Edecay=1.8+/-0.1 MeV, Gamma = 0.8+/-0.4 MeV) consistent with a soft-dipole\nexcitation.", + "category": "nucl-ex" + }, + { + "text": "Determination of gamma-ray widths in $^{15}$N using nuclear resonance\n fluorescence: The stable nucleus $^{15}$N is the mirror of $^{15}$O, the bottleneck in the\nhydrogen burning CNO cycle. Most of the $^{15}$N level widths below the proton\nemission threshold are known from just one nuclear resonance fluorescence (NRF)\nmeasurement, with limited precision in some cases. A recent experiment with the\nAGATA demonstrator array determined level lifetimes using the Doppler Shift\nAttenuation Method (DSAM) in $^{15}$O. As a reference and for testing the\nmethod, level lifetimes in $^{15}$N have also been determined in the same\nexperiment. The latest compilation of $^{15}$N level properties dates back to\n1991. The limited precision in some cases in the compilation calls for a new\nmeasurement in order to enable a comparison to the AGATA demonstrator data. The\nwidths of several $^{15}$N levels have been studied with the NRF method. The\nsolid nitrogen compounds enriched in $^{15}$N have been irradiated with\nbremsstrahlung. The $\\gamma$-rays following the deexcitation of the excited\nnuclear levels were detected with four HPGe detectors. Integrated\nphoton-scattering cross sections of ten levels below the proton emission\nthreshold have been measured. Partial gamma-ray widths of ground-state\ntransitions were deduced and compared to the literature. The photon scattering\ncross sections of two levels above the proton emission threshold, but still\nbelow other particle emission energies have also been measured, and proton\nresonance strengths and proton widths were deduced. Gamma and proton widths\nconsistent with the literature values were obtained, but with greatly improved\nprecision.", + "category": "nucl-ex" + }, + { + "text": "Energy loss for heavy quarks in relation to light partons; is radiative\n energy loss for heavy quarks anomalous?: The scaling properties of jet suppression measurements are compared for\nnon-photonic electrons ($e^{\\pm}$) and neutral pions ($\\pi^0$) in Au + Au\ncollisions at $\\sqrt{s_{NN}}=200$ GeV. For a broad range of transverse momenta\nand collision centralities, the comparison is consistent with jet quenching\ndominated by radiative energy loss for both heavy and light partons. Less\nquenching is indicated for heavy quarks via $e^{\\pm}$; this gives an\nindependent estimate of the transport coefficient $\\hat{q}$ that agrees with\nits magnitude obtained from quenching of light partons via $\\pi^0$'s.", + "category": "nucl-ex" + }, + { + "text": "Electromagnetic M1 transition strengths from inelastic proton\n scattering: The cases of 48Ca and 208Pb: Inelastic proton scattering at energies of a few hundred MeV and extreme\nforward angles selectively excites the isovector spin-flip M1 (IVSM1)\nresonance. A method based on isospin symmetry is presented to extract its\nelectromagnetic transition strength from the (p,p') cross sections. It is\napplied to 48Ca, a key case for an interpretation of the quenching phenomenon\nof the spin-isospin response, and leads to a M1 strength consistent with an\nolder (e,e') experiment excluding the almost two times larger value from a\nrecent (\\gamma,n) experiment. Good agreement with electromagnetic probes is\nobserved in 208Pb suggesting the possibility to extract systematic information\non the IVSM1 resonance in heavy nuclei.", + "category": "nucl-ex" + }, + { + "text": "High-spin states in and around doubly-magic nuclei: The study of high-spin states in regions of doubly-magic nuclei performed\nwith the use of deep-inelastic heavy ion reactions is reviewed. New and\ntentative results concerning high-spin states in the 48Ca and yrast structures\nin 47Ca, 47K, 49Ca and 49Sc isotopes are presented. The status of the high-spin\nstate study in the region of 132Sn and 208Pb is outlined, including discussion\nof recently obtained results in the 208Pb core and the 206Hg two-proton-hole\nnucleus.", + "category": "nucl-ex" + }, + { + "text": "Search for $^{22}$Na in novae supported by a novel method for measuring\n femtosecond nuclear lifetimes: Classical novae are thermonuclear explosions in stellar binary systems, and\nimportant sources of $^{26}$Al and $^{22}$Na. While gamma rays from the decay\nof the former radioisotope have been observed throughout the Galaxy, $^{22}$Na\nremains untraceable. The half-life of $^{22}$Na (2.6 yr) would allow the\nobservation of its 1.275 MeV gamma-ray line from a cosmic source. However, the\nprediction of such an observation requires good knowledge of the nuclear\nreactions involved in the production and destruction of this nucleus. The\n$^{22}$Na($p,\\gamma$)$^{23}$Mg reaction remains the only source of large\nuncertainty about the amount of $^{22}$Na ejected. Its rate is dominated by a\nsingle resonance on the short-lived state at 7785.0(7) keV in $^{23}$Mg. In the\npresent work, a combined analysis of particle-particle correlations and\nvelocity-difference profiles is proposed to measure femtosecond nuclear\nlifetimes. The application of this novel method to the study of the $^{23}$Mg\nstates, combining magnetic and highly-segmented tracking gamma-ray\nspectrometers, places strong limits on the amount of $^{22}$Na produced in\nnovae, explains its non-observation to date in gamma rays (flux < 2.5x$10^{-4}$\nph/(cm$^2$s)), and constrains its detectability with future space-borne\nobservatories.", + "category": "nucl-ex" + }, + { + "text": "Charge-changing cross sections for $^{42\\textrm{--}51}$Ca and effect of\n charged-particle evaporation induced by neutron removal reaction: Charge-changing cross sections $\\sigma_\\mathrm{CC}$ for\n$^{42\\textrm{--}51}$Ca on a carbon target at around 280~MeV/nucleon have been\nmeasured. The measured $\\sigma_\\mathrm{CC}$ values differ significantly from\nthe previously developed calculations based on the Glauber model. However,\nthrough introduction of the charged-particle evaporation effect induced by the\nneutron-removal reaction in addition to the Glauber-model calculation,\nexperimental $\\sigma_\\mathrm{CC}$ values on $^{12}$C at around 300~MeV/nucleon\nfor nuclides from C to Fe isotopes are all reproduced with approximately 1\\%\naccuracy. This proposed model systematically reproduces $\\sigma_\\mathrm{CC}$\ndata without phenomenological corrections, and can also explain experimental\n$\\sigma_\\mathrm{CC}$ values obtained in other energy regions.", + "category": "nucl-ex" + }, + { + "text": "Study of Two-Photon Exchange via the Beam Transverse Single Spin\n Asymmetry in Electron-Proton Elastic Scattering at Forward Angles over a Wide\n Energy Range: We report on a new measurement of the beam transverse single spin asymmetry\nin electron-proton elastic scattering, $A^{ep}_{\\perp}$, at five beam energies\nfrom 315.1 MeV to 1508.4 MeV and at a scattering angle of $30^{\\circ} < \\theta\n< 40^{\\circ}$. The covered $Q^2$ values are 0.032, 0.057, 0.082, 0.218, 0.613\n(GeV/c)$^2$. The measurement clearly indicates significant inelastic\ncontributions to the two-photon-exchange (TPE) amplitude in the low-$Q^2$\nkinematic region. No theoretical calculation is able to reproduce our result.\nComparison with a calculation based on unitarity, which only takes into account\nelastic and $\\mathrm{\\pi N}$ inelastic intermediate states, suggests that there\nare other inelastic intermediate states such as $\\mathrm{\\pi \\pi N}$,\n$\\mathrm{K \\Lambda}$ and $\\mathrm{\\eta N}$. Covering a wide energy range, our\nnew high-precision data provide a benchmark to study those intermediate states.", + "category": "nucl-ex" + }, + { + "text": "Open heavy-flavour measurements in pp and Pb-Pb collisions with ALICE at\n the LHC: We present an overview of measurements related to open heavy-flavour\nproduction with the ALICE experiment at the LHC. Studies are performed using\nsingle leptons (electrons at mid-rapidity and muons at forward-rapidity) and D\nmesons, which are reconstructed via their hadronic decay channels. The measured\ndifferential production cross sections in proton-proton collisions at\n$\\sqrt{s}$ = 2.76 and 7 TeV are in agreement with perturbative QCD\ncalculations. Results from Pb-Pb collisions at $\\sqrt{s_{NN}}$ = 2.76 TeV on\nthe nuclear modification factor $R_{AA}$ are shown, along with the elliptic\nflow $\\nu_2$.", + "category": "nucl-ex" + }, + { + "text": "Production and electromagnetic decay of hyperons: a feasibility study\n with HADES as a Phase-0 experiment at FAIR: A feasibility study has been performed in order to investigate the\nperformance of the HADES detector to measure the electromagnetic decays of the\nhyperon resonances $\\Sigma(1385)^0$, $\\Lambda(1405)$ and\n$\\Lambda{\\Lambda}(1520)$ as well as the production of double strange baryon\nsystems $\\Xi^-$ and $\\Lambda\\Lambda$ in p+p reactions at a beam kinetic energy\nof 4.5 GeV. The existing HADES detector will be upgraded by a new Forward\nDetector, which extends the detector acceptance into a range of polar angles\nthat plays a crucial role for these investigations. The analysis of each\nchannel is preceded by a consideration of the production cross-sections.\nAfterwards the expected signal count rates using a target consisting of either\nliquid hydrogen or polyethylene are summarized.", + "category": "nucl-ex" + }, + { + "text": "Heavy Flavour measurements in Pb$-$Pb collisions with the upgraded ALICE\n Inner Tracking System: During the second LHC long shutdown (LS2) the Inner Tracking System (ITS) of\nALICE (A Large Ion Collider Experiment) will be replaced by seven layers of\nCMOS Monolithic Active Pixel Sensors (MAPS). The latest innovations in silicon\nimaging technology allow for the construction of large, ultra-thin silicon\nwafers which can further improve the capabilities of the ALICE tracker. The\nresearch and development studies towards the construction of a novel vertex\ndetector have started. The detector installation has been proposed for the\nthird LHC long shutdown (LS3) during which the three innermost layers shall be\nreplaced by three cylindrical layers of large curved CMOS wafers. This upgrade\n(ITS3) will further improve the impact parameter resolution and the tracking\nefficiency of low momentum particles. The innermost layer will be positioned\ncloser to the interaction point and the material budget will be reduced down to\n0.05$\\%X_0$ per layer. Monte Carlo simulations of a simplified ITS3 geometry\nwithin the ITS2 design indicate an improvement in the impact parameter\nresolution and the tracking efficiency, which are of crucial importance for\nmeasurements of heavy-flavour hadrons. This contribution shows the improved\nperformance for the example of the $\\Lambda_{\\mathrm{b}}$, for which the\nsignificance of its measurement is extracted based on these MC simulations. A\nsignificant improvement by almost a factor of three in the low momentum region\ncompared to the ITS2 is observed.", + "category": "nucl-ex" + }, + { + "text": "Recent Findings from Heavy-Flavor Angular Correlation Measurements in\n Hadronic Collisions: The study of angular correlations of heavy-flavor particles in hadronic\ncollisions can provide crucial insight into the heavy quark production,\nshowering, and hadronization processes. The comparison with model predictions\nallows us to discriminate among different approaches for heavy quark production\nand hadronization, as well as different treatments of the underlying event\nemployed by the models to reproduce correlation observables. In\nultra-relativistic heavy-ion collisions, where a deconfined state of matter,\nthe quark--gluon plasma (QGP), is created, heavy-flavor correlations can shed\nlight on the modification of the heavy quark fragmentation due to the\ninteraction between charm and beauty quarks with the QGP constituents, as well\nas characterize their energy loss processes while traversing the medium.\nInsight into the possible emergence of collective-like mechanisms in smaller\nsystems, resembling those observed in heavy-ion collisions, can also be\nobtained by performing correlation studies in high-multiplicity proton--proton\nand proton--nucleus collisions. In this review, the most recent and relevant\nmeasurements of heavy-flavor correlations performed in all collision systems at\nthe LHC and RHIC will be presented, and the new understandings that they\nprovide will be discussed.", + "category": "nucl-ex" + }, + { + "text": "New experimental limits on the alpha decays of lead isotopes: For the first time a PbWO4 crystal was grown using ancient Roman lead and it\nwas run as a cryogenic detector. Thanks to the simultaneous and independent\nread-out of heat and scintillation light, the detector was able to discriminate\nbeta/gamma interactions with respect to alpha particles down to low energies.\nNew more stringent limits on the alpha decays of the lead isotopes are\npresented. In particular a limit of T_{1/2} > 1.4*10^20 y at a 90% C.L. was\nevaluated for the alpha decay of 204Pb to 200Hg.", + "category": "nucl-ex" + }, + { + "text": "The reactor antineutrino spectrum calculation: New fissile isotopes antineutrino spectra ($^{235}$U, $^{238}$U, $^{239}$Pu\nand $^{241}$Pu) calculation is presented. On base of summation method the toy\nmodel was developed. It was shown that total antineutrino number is conserved\nin framework of given database on individual fragments yields. The analysis of\nantineutrino spectrum shape says that any presented antineutrino spectrum\nshould satisfy to the total antineutrino number conservation.", + "category": "nucl-ex" + }, + { + "text": "a0+(980)-resonance production in the reaction pp -> dpi+eta close to the\n K(bar(K)) threshold: The reaction pp -> dpi+eta has been measured at a beam energy of T=2.65 GeV\n(p=3.46 GeV/c) using the ANKE spectrometer at COSY-Juelich. The missing mass\ndistribution of the detected dpi+ pairs exhibits a peak around the eta mass on\ntop of a strong background of multi-pion pp -> dpi+(n(pi)) events. The\ndifferential cross section d^4(sigma)/d(Omega_d)d(Omega_pi+)d(p_d)d(p_pi+) for\nthe reaction pp -> dpi+eta has been determined model independently for two\nregions of phase space. Employing a dynamical model for the a0+ production\nallows one then to deduce a total cross section of sigma(pp -> da0+ ->\ndpi+eta)=(1.1 +/- 0.3_(stat) +/- 0.7_(syst)) microbarn for the production of\npi+eta via the scalar a0+(980) resonance and sigma(pp -> dpi+eta) = (3.5 +/-\n0.3_(stat) +/- 1.0_(syst)) microbarn for the non-resonant production. Using the\nsame model as for the interpretation of recent results from ANKE for the\nreaction pp -> dK+(bar(K0)), the ratio of the total cross sections is sigma(pp\n-> d(K+(bar(K0)))_(L=0))/sigma(pp -> da0+ -> dpi+eta) = 0.029 +/- 0.008_(stat)\n+/- 0.009_(syst), which is in agreement with branching ratios in the\nliterature.", + "category": "nucl-ex" + }, + { + "text": "Signals of a Critical Behavior in Peripheral Au + Au Collisions at 35\n MeV/nucleon: Multifragment events resulting from peripheral Au + Au collisions at 35\nMeV/nucleon are analysed in terms of critical behavior. The analysis of most of\ncriticality signals proposed so far (conditional moments of charge\ndistributions, Campi scatter plot, fluctuations of the size of the largest\nfragment, intermittency analysis) is consistent with the occurrence of a\ncritical behavior of the system.", + "category": "nucl-ex" + }, + { + "text": "Identified high-$p_{T}$ spectra in Cu+Cu collisions at\n $\\sqrt{s_{NN}}$=200 GeV: We report new results on identified (anti)proton and charged pion spectra at\nlarge transverse momenta (3<$p_{T}$<10 GeV/c) from Cu+Cu collisions at\n$\\sqrt{s_{NN}}$=200 GeV using the STAR detector at the Relativistic Heavy Ion\nCollider (RHIC). This study explores the system size dependence of two novel\nfeatures observed at RHIC with heavy ions: the hadron suppression at\nhigh-$p_{T}$ and the anomalous baryon to meson enhancement at intermediate\ntransverse momenta. Both phenomena could be attributed to the creation of a new\nform of QCD matter. The results presented here bridge the system size gap\nbetween the available pp and Au+Au data, and allow the detailed exploration for\nthe on-set of the novel features. Comparative analysis of all available 200 GeV\ndata indicates that the system size is a major factor determining both the\nmagnitude of the hadron spectra suppression at large transverse momenta and the\nrelative baryon to meson enhancement.", + "category": "nucl-ex" + }, + { + "text": "Measurements of Nuclear Level Densities and Gamma-Ray Strength Functions\n and their Interpretations: A method to extract primary $\\gamma$-ray spectra from particle-$\\gamma$\ncoincidences at excitation energies up to the neutron binding energy is\ndescribed. From these spectra, the level density and $\\gamma$-ray strength\nfunction can be determined. From the level density, several thermodynamical\nquantities are obtained within the microcanonical and canonical ensemble. Also\nmodels for the $\\gamma$-ray strength function are discussed.", + "category": "nucl-ex" + }, + { + "text": "First measurement of $^{30}$S+$\u03b1$ resonant elastic scattering for\n the $^{30}$S($\u03b1$,p) reaction rate: Background: Type I x-ray bursts are the most frequent thermonuclear\nexplosions in the galaxy, resulting from thermonuclear runaway on the surface\nof an accreting neutron star. The $^{30}$S($\\alpha$,p) reaction plays a\ncritical role in burst models, yet insufficient experimental information is\navailable to calculate a reliable, precise rate for this reaction. Purpose: Our\nmeasurement was conducted to search for states in $^{34}$Ar and determine their\nquantum properties. In particular, natural-parity states with large\n$\\alpha$-decay partial widths should dominate the stellar reaction rate.\nMethod: We performed the first measurement of $^{30}$S+$\\alpha$ resonant\nelastic scattering up to a center-of-mass energy of 5.5 MeV using a radioactive\nion beam. The experiment utilized a thick gaseous active target system and\nsilicon detector array in inverse kinematics. Results: We obtained an\nexcitation function for $^{30}$S($\\alpha$,$\\alpha$) near $150^{\\circ}$ in the\ncenter-of-mass frame. The experimental data were analyzed with an $R$-Matrix\ncalculation, and we observed three new resonant patterns between 11.1 and 12.1\nMeV, extracting their properties of resonance energy, widths, spin, and parity.\nConclusions: We calculated the resonant thermonuclear reaction rate of\n$^{30}$S($\\alpha$,p) based on all available experimental data of $^{34}$Ar and\nfound an upper limit about one order of magnitude larger than a rate determined\nusing a statistical model. The astrophysical impact of these two rates has been\ninvestigated through one-zone postprocessing type I x-ray burst calculations.\nWe find that our new upper limit for the $^{30}$S($\\alpha$,p)$^{33}$Cl rate\nsignificantly affects the predicted nuclear energy generation rate during the\nburst.", + "category": "nucl-ex" + }, + { + "text": "PHENIX results on Bose-Einstein correlation functions: Measurement of Bose-Einstein or HBT correlations of identified charged\nparticles provide insight into the space-time structure of particle emitting\nsources in heavy-ion collisions. In this paper we present the latest results\nfrom the RHIC PHENIX experiment on such measurements.", + "category": "nucl-ex" + }, + { + "text": "Light (anti)nuclei production in Pb-Pb collisions at\n $\\sqrt{s_{\\mathrm{NN}}}=5.02$ TeV: The measurement of the production of deuterons, tritons and $^{3}\\mathrm{He}$\nand their antiparticles in Pb-Pb collisions at $\\sqrt{s_{\\mathrm{NN}}} = 5.02$\nTeV is presented in this article. The measurements are carried out at\nmidrapidity ($|y| < $ 0.5) as a function of collision centrality using the\nALICE detector. The $p_{\\rm T}$-integrated yields, the coalescence parameters\nand the ratios to protons and antiprotons are reported and compared with\nnucleosynthesis models. The comparison of these results in different collision\nsystems at different centre-of-mass collision energies reveals a suppression of\nnucleus production in small systems. In the Statistical Hadronisation Model\nframework, this can be explained by a small correlation volume where the baryon\nnumber is conserved, as already shown in previous fluctuation analyses.\nHowever, a different size of the correlation volume is required to describe the\nproton yields in the same data sets. The coalescence model can describe this\nsuppression by the fact that the wave functions of the nuclei are large and the\nfireball size starts to become comparable and even much smaller than the actual\nnucleus at low multiplicities.", + "category": "nucl-ex" + }, + { + "text": "Excited Baryon Structure Using Exclusive Reactions with CLAS12: Studying excited nucleon structure through exclusive electroproduction\nreactions is an important avenue for exploring the nature of the\nnon-perturbative strong interaction. Electrocouplings for $N^*$ states in the\nmass range below 1.8~GeV have been determined from analyses of CLAS $\\pi N$,\n$\\eta N$, and $\\pi \\pi N$ data. This work made it clear that consistency of\nindependent analyses of exclusive channels with different couplings and\nnon-resonant backgrounds but the same $N^*$ electro-excitation amplitudes, is\nessential to have confidence in the extracted results. In terms of hadronic\ncoupling, many high-lying $N^*$ states preferentially decay through the $\\pi\n\\pi N$ channel instead of $\\pi N$. Data from the $KY$ channels will therefore\nbe critical to provide an independent analysis to compare the extracted\nelectrocouplings for the high-lying $N^*$ states against those determined from\nthe $\\pi N$ and $\\pi \\pi N$ channels. A program to study excited $N^*$ decays\nto non-strange and strange exclusive final states using CLAS12 will measure\ndifferential cross sections to be used as input to extract the $\\gamma_vNN^*$\ntransition form factors for the most prominent $N^*$ states in the range of\ninvariant energy $W$ up 3~GeV in the virtually unexplored domain of momentum\ntransfers $Q^2$ up to 12~GeV$^2$.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal anisotropy in U+U collisions at STAR: The azimuthal anisotropy of particle production is commonly used in\nhigh-energy nuclear collisions to study the early evolution of the expanding\nsystem. The prolate shape of uranium nuclei makes it possible to study how the\ngeometry of the colliding nuclei affects final state anisotropies. It also\nprovides a unique opportunity to understand how entropy is produced in heavy\nion collisions. In this paper, the two- and four- particle cumulant $v_2$\n($v_{2}\\{2\\}$ and $v_{2}\\{4\\}$) from U+U collisions at $\\sqrt{s_{NN}}$ = 193\nGeV and Au+Au collisions at $\\sqrt{s_{NN}}$ = 200 GeV for inclusive charged\nhadrons will be presented. The STAR Zero Degree Calorimeters are used to select\nvery central collisions. Differences were observed between the multiplicity\ndependence of $v_{2}\\{2\\}$ for most central Au+Au and U+U collisions. The\nmultiplicity dependence of $v_{2}\\{2\\}$ in central collisions were compared to\nMonte Carlo Glauber model predictions and it was seen that this model cannot\nexplain the present results.", + "category": "nucl-ex" + }, + { + "text": "Multiplicity and transverse momentum dependence of charge-balance\n functions in pPb and PbPb collisions at LHC energies: Measurements of the charge-dependent two-particle angular correlation\nfunction in proton-lead (pPb) collisions at a nucleon-nucleon center-of-mass\nenergy of $\\sqrt{s_\\mathrm{NN}}$ = 8.16 TeV and lead-lead (PbPb) collisions\nat$\\sqrt{s_\\mathrm{NN}}$ = 5.02 TeV are reported. The pPb and PbPb datasets\ncorrespond to integrated luminosities of 186\\nbinv and 0.607 nb$^{-1}$,\nrespectively, and were collected using the CMS detector at the CERN LHC. The\ncharge-dependent correlations are characterized by balance functions of same-\nand opposite-sign particle pairs. The balance functions, which contain\ninformation about the creation time of charged particle pairs and the\ndevelopment of collectivity, are studied as functions of relative\npseudorapidity ($\\Delta \\eta$) and relative azimuthal angle ($\\Delta \\phi$),\nfor various multiplicity and transverse momentum ($p_\\mathrm{T}$) intervals. A\nmultiplicity dependence of the balance function is observed in $\\Delta \\eta$\nand $\\Delta \\phi$ for both systems. The width of the balance functions\ndecreases towards high-multiplicity collisions in the momentum region $\\lt$2\nGeV, for pPb and PbPb results. No multiplicity dependence is observed at higher\ntransverse momentum. The data are compared with HYDJET, HIJING and AMPT\ngenerator predictions, none of which capture completely the multiplicity\ndependence seen in the data.", + "category": "nucl-ex" + }, + { + "text": "Decomposition of flow and nonflow in relativistic heavy-ion collisions: We propose a method to separate \\Delta\\eta-dependent and\n\\Delta\\eta-independent azimuthal correlations using two- and four-particle\ncumulants between pseudo-rapidity (\\eta) bins in symmetric heavy-ion\ncollisions. The \\Delta\\eta-independent correlation may be dominated by harmonic\nflows, a global correlation to the common collision geometry. The\n\\Delta\\eta-dependent correlation can be identified as nonflow, particle\ncorrelations unrelated to the common geometry. Our method exploits the \\eta\nsymmetry of the average harmonic flows and is \"data-driven.\" We use the AMPT\nand HIJING event generators to illustrate our method. We discuss the decomposed\n\\Delta\\eta-independent and \\Delta\\eta-dependent correlations regarding flow and\nnonflow in the models.", + "category": "nucl-ex" + }, + { + "text": "Formation of the intermediate baryon systems in hadron-nuclear and\n nuclear-nuclear interactions: The centrality experiments indicate regime change and saturation in the\nbehavior of some characteristics of the secondary particles emitted in\nhadron-nuclear and nuclear-nuclear interactions at high energies. The\nphenomenon has a critical character. The simple models do not explain the\neffect. We suppose that the responsible mechanism to explain the phenomenon\ncould be the formation and decay of the intermediate baryon systems. Such\nsystems could be formed as a result of nucleon percolation in compressed\nbaryonic matter. Formation of big percolation cluster may change the properties\nof the medium, e.g., it could lead to the changing its transparency. This could\nbe used to get a signal of the intermediate baryonic system formation. We\nconsider two signals to identify the formation of the intermediate baryon\nsystems: the critical changing of transparency of the strongly interacting\nmatter and the enhancement of light nuclei production with increase in\ncentrality.", + "category": "nucl-ex" + }, + { + "text": "Probing small Bjorken-$x$ nuclear gluonic structure via coherent\n J/$\u03c8$ photoproduction in ultraperipheral PbPb collisions at\n $\\sqrt{s_\\mathrm{NN}}$ = 5.02 TeV: Quasireal photons exchanged in relativistic heavy ion interactions are\npowerful probes of the gluonic structure of nuclei. The coherent J/$\\psi$\nphotoproduction cross section in ultraperipheral lead-lead collisions is\nmeasured as a function of photon-nucleus center-of-mass energies per nucleon\n(W$^\\text{Pb}_{\\gamma\\text{N}}$), over a wide range of 40 $\\lt$\nW$^\\text{Pb}_{\\gamma\\text{N}}$ $\\lt$ 400 GeV. Results are obtained using data\nat the nucleon-nucleon center-of-mass energy of 5.02 TeV collected by the CMS\nexperiment at the CERN LHC, corresponding to an integrated luminosity of 1.52\nnb$^{-1}$. The cross section is observed to rise rapidly at low\nW$^\\text{Pb}_{\\gamma\\text{N}}$, and plateau above\nW$^\\text{Pb}_{\\gamma\\text{N}}$ $\\approx$ 40 GeV, up to 400 GeV, a new regime of\nsmall Bjorken-$x$ ($\\approx$ 6 $\\times$ 10$^{-5}$) gluons being probed in a\nheavy nucleus. The observed energy dependence is not predicted by current\nquantum chromodynamic models.", + "category": "nucl-ex" + }, + { + "text": "Azimuthal anisotropy of neutral pion production in Au+Au collisions at\n sqrt(s_NN) = 200 GeV: Path-length dependence of jet quenching and the role of\n initial geometry: We have measured the azimuthal anisotropy of pi0's for 1 < pT < 18 GeV/c for\nAu+Au collisions at sqrt s_NN = 200 GeV. The observed anisotropy shows a\ngradual decrease in 3 < pT < 7 - 10 GeV/c, but remains positive beyond 10\nGeV/c. The magnitude of this anisotropy is under-predicted, up to at least 10\nGeV/c, by current perturbative QCD (pQCD) energy-loss model calculations. An\nestimate of the increase in anisotropy expected from initial-geometry\nmodification due to gluon saturation effects and initial-geometry fluctuations\nis insufficient to account for this discrepancy. Calculations which implement a\npath length dependence steeper than what is implied by current pQCD energy-loss\nmodels, show reasonable agreement with the data.", + "category": "nucl-ex" + }, + { + "text": "J/Psi Elliptic Flow in Pb-Pb Collisions at $\\sqrt{s_{\\rm NN}}$ = 2.76\n TeV: We report on the first measurement of inclusive J/$\\psi$ elliptic flow,\n$v_2$, in heavy-ion collisions at the LHC. The measurement is performed with\nthe ALICE detector in Pb-Pb collisions at $\\sqrt{s_{\\rm NN}} = 2.76$ TeV in the\nrapidity range $2.5 < y < 4.0$. The dependence of the J/$\\psi$ $v_2$ on the\ncollision centrality and on the J/$\\psi$ transverse momentum is studied in the\nrange $0 < p_{\\rm T} < 10$ GeV/$c$. For semi-central Pb-Pb collisions at\n$\\sqrt{s_{\\rm NN}} = 2.76$ TeV, an indication of non-zero $v_2$ is observed\nwith a maximum value of $v_2 = 0.116 \\pm 0.046 {\\rm (stat.)} \\pm 0.029 {\\rm\n(syst.)}$ for J/$\\psi$ in the transverse momentum range $2 < p_{\\rm T} < 4$\nGeV/$c$. The elliptic flow measurement complements the previously reported\nALICE results on the inclusive J/$\\psi$ nuclear modification factor and favors\nthe scenario of a significant fraction of J/$\\psi$ production from charm quarks\nin a deconfined partonic phase.", + "category": "nucl-ex" + }, + { + "text": "SuperNEMO double beta decay experiment: SuperNEMO is a next-generation double beta decay experiment based on the\nsuccessful tracking plus calorimetry design approach of the recently stopped\nNEMO3 experiment. SuperNEMO can study a range of isotopes, but the baseline\nisotope is $^{82}$Se. The total isotope mass will be 100--200 kg. A sensitivity\nto a $0\\nu\\beta\\beta$ half-life greater than $10^{26}$ years can be reached\nwhich gives access to Majorana neutrino masses of 50--100 meV. Having\nsuccessfully completed R&D stage the SuperNEMO Collaboration has commenced the\nconstruction of the first module, the Demonstrator. The present status of\nSuperNEMO program and plan for the nearest future are discussed.", + "category": "nucl-ex" + }, + { + "text": "Elastic proton-deuteron scattering at intermediate energies: Observables in elastic proton-deuteron scattering are sensitive probes of the\nnucleon-nucleon interaction and three-nucleon force effects. The present\nexperimental data base for this reaction is large, but contains a large\ndiscrepancy between data sets for the differential cross section taken at 135\nMeV/nucleon by two experimental research groups. This paper reviews the\nbackground of this problem and presents new data taken at KVI. Differential\ncross sections and analyzing powers for the $^{2}{\\rm H}(\\vec p,d){p}$ and\n${\\rm H}(\\vec d,d){p}$ reactions at 135 MeV/nucleon and 65 MeV/nucleon,\nrespectively, have been measured. The data differ significantly from previous\nmeasurements and consistently follow the energy dependence as expected from an\ninterpolation of published data taken over a large range at intermediate\nenergies.", + "category": "nucl-ex" + }, + { + "text": "A new event generator for the elastic scattering of charged leptons on\n protons: This paper describes a new multipurpose event generator, ESEPP, which has\nbeen developed for the Monte Carlo simulation of unpolarized elastic scattering\nof charged leptons on protons. The generator takes into account the\nlowest-order QED radiative corrections to the Rosenbluth cross section\nincluding first-order bremsstrahlung without using the soft-photon or\nultrarelativistic approximations. ESEPP can be useful for several significant\nongoing and planned experiments.", + "category": "nucl-ex" + }, + { + "text": "Measuring K$^0_{\\rm S}$K$^{\\rm \\pm}$ interactions using Pb-Pb collisions\n at ${\\sqrt{s_{\\rm NN}}=2.76}$ TeV: We present the first ever measurements of femtoscopic correlations between\nthe K$^0_{\\rm S}$ and K$^{\\rm \\pm}$ particles. The analysis was performed on\nthe data from Pb-Pb collisions at $\\sqrt{s_{\\rm NN}}=2.76$ TeV measured by the\nALICE experiment. The observed femtoscopic correlations are consistent with\nfinal-state interactions proceeding via the $a_0(980)$ resonance. The extracted\nkaon source radius and correlation strength parameters for K$^0_{\\rm S}$K$^{\\rm\n-}$ are found to be equal within the experimental uncertainties to those for\nK$^0_{\\rm S}$K$^{\\rm +}$. Comparing the results of the present study with those\nfrom published identical-kaon femtoscopic studies by ALICE, mass and coupling\nparameters for the $a_0$ resonance are constrained. Our results are also\ncompatible with the interpretation of the $a_0$ having a tetraquark structure\nover that of a diquark.", + "category": "nucl-ex" + }, + { + "text": "$^{179}$Ta(n,$\u03b3$) cross-section measurement and the astrophysical\n origin of $^{180}$Ta isotope: Tantalum-180m is nature's rarest (quasi) stable isotope and its astrophysical\norigin is an open question. A possible production site of this isotope is the\nslow neutron capture process in Asymptotic Giant Branch stars, where it can be\nproduced via neutron capture reactions on unstable $^{179}$Ta. We report a new\nmeasurement of the $^{179}$Ta($n,\\gamma$)$^{180}$Ta cross section at thermal\nneutron energies via the activation technique. Our results for the thermal and\nresonance-integral cross-sections are 952 $\\pm$ 57 b and 2013 $\\pm$ 148 b,\nrespectively. The thermal cross section is in good agreement with the only\nprevious measurement (Phys. Rev C {\\bf 60} 025802, 1999), while the resonance\nintegral is different by a factor of $\\approx$1.7. While neutron energies in\nthis work are smaller than the energies in a stellar environment, our results\nmay lead to improvements in theoretical predictions of the stellar cross\nsection.", + "category": "nucl-ex" + }, + { + "text": "Bremsstrahlung from relativistic heavy ions in a fixed target experiment\n at the LHC: We calculate the emission of bremsstrahlung from lead and argon ions in A\nFixed Target ExpeRiment (AFTER) that uses the LHC beams. With nuclear charges\nof $Ze$ equal $208$ and $18$ respectively, these ions are accelerated to\nenergies of $7$ TeV$\\times Z $. The bremsstrahlung peaks around $\\approx 100$\nGeV and the spectrum exposes the nuclear structure of the incoming ion. The\npeak structure is significantly different from the flat power spectrum\npertaining to a point charge. Photons are predominantly emitted within an angle\nof $1/\\gamma$ to the direction of ion propagation. Our calculations are based\non the Weizs\\\"{a}cker-Williams method of virtual quanta with application of\nexisting experimental data on photonuclear interactions.", + "category": "nucl-ex" + }, + { + "text": "The Structure of the Nucleon: Elastic Electromagnetic Form Factors: Precise proton and neutron form factor measurements at Jefferson Lab, using\nspin observables, have recently made a significant contribution to the\nunraveling of the internal structure of the nucleon. Accurate experimental\nmeasurements of the nucleon form factors are a test-bed for understanding how\nthe nucleon's static properties and dynamical behavior emerge from QCD, the\ntheory of the strong interactions between quarks. There has been enormous\ntheoretical progress, since the publication of the Jefferson Lab proton form\nfactor ratio data, aiming at reevaluating the picture of the nucleon. We will\nreview the experimental and theoretical developments in this field and discuss\nthe outlook for the future.", + "category": "nucl-ex" + }, + { + "text": "Dressed Spin of Polarized 3He in a Cell: We report a measurement of the modification of the effective precession\nfrequency of polarized 3He atoms in response to a dressing field in a room\ntemperature cell. The 3He atoms were polarized using the metastability\nspin-exchange method. An oscillating dressing field is then applied\nperpendicular to the constant magnetic field. Modification of the 3He effective\nprecession frequency was observed over a broad range of the amplitude and\nfrequency of the dressing field. The observed effects are compared with\ncalculations based on quantum optics formalism.", + "category": "nucl-ex" + }, + { + "text": "Direct jet reconstruction in p + p and Cu + Cu at PHENIX: The Relativistic Heavy Ion Collider collides heavy nuclei at\nultrarelativistic energies, creating a strongly interacting, partonic medium\nthat is opaque to the passage of high energy quarks and gluons. Direct jet\nreconstruction applied to these collision systems provides a crucial constraint\non the mechanism for in-medium parton energy loss and jet-medium interactions.\nHowever, traditional jet reconstruction algorithm operating in the large soft\nbackground at RHIC give rise to fake jets well above the intrinsic production\nrate of high-pT partons, impeding the detection of the low cross section jet\nsignal at RHIC energies. We developed a new jet reconstruction algorithm that\nuses a Gaussian filter to locate and reconstruct the jet energy. This algorithm\nis combined with a fake jet rejection scheme that provides efficient jet\nreconstruction with acceptable fake rate in a background environment up to the\ncentral Au + Au collision at sqrt(s_NN) = 200 GeV. We present results of its\napplication in p + p and Cu + Cu collisions using data from the PHENIX\ndetector, namely p + p cross section, Cu + Cu jet yields, the Cu + Cu nuclear\nmodification factor, and Cu + Cu jet-jet azimuthal correlation.", + "category": "nucl-ex" + }, + { + "text": "Beam-Energy Dependence of Charge Balance Functions from Au+Au Collisions\n at RHIC: Balance functions have been measured in terms of relative pseudorapidity\n($\\Delta \\eta$) for charged particle pairs at the Relativistic Heavy-Ion\nCollider (RHIC) from Au+Au collisions at $\\sqrt{s_{\\rm NN}}$ = 7.7 GeV to 200\nGeV using the STAR detector. These results are compared with balance functions\nmeasured at the Large Hadron Collider (LHC) from Pb+Pb collisions at\n$\\sqrt{s_{\\rm NN}}$ = 2.76 TeV by the ALICE Collaboration. The width of the\nbalance function decreases as the collisions become more central and as the\nbeam energy is increased. In contrast, the widths of the balance functions\ncalculated using shuffled events show little dependence on centrality or beam\nenergy and are larger than the observed widths. Balance function widths\ncalculated using events generated by UrQMD are wider than the measured widths\nin central collisions and show little centrality dependence. The measured\nwidths of the balance functions in central collisions are consistent with the\ndelayed hadronization of a deconfined quark gluon plasma (QGP). The narrowing\nof the balance function in central collisions at $\\sqrt{s_{\\rm NN}}$ = 7.7 GeV\nimplies that a QGP is still being created at this relatively low energy.", + "category": "nucl-ex" + }, + { + "text": "Cross sections and Rosenbluth separations in 1H(e, e'K+)Lambda up to\n Q2=2.35 GeV2: The kaon electroproduction reaction 1H(e,e'K+)Lambda was studied as a\nfunction of the virtual-photon four-momentum, Q2, total energy, W, and momentum\ntransfer, t, for different values of the virtual- photon polarization\nparameter. Data were taken at electron beam energies ranging from 3.40 to 5.75\nGeV. The center of mass cross section was determined for 21 kinematics\ncorresponding to Q2 of 1.90 and 2.35 GeV2 and the longitudinal, sigmaL, and\ntransverse, sigmaT, cross sections were separated using the Rosenbluth\ntechnique at fixed W and t. The separated cross sections reveal a flat energy\ndependence at forward kaon angles not satisfactorily described by existing\nelectroproduction models. Influence of the kaon pole on the cross sections was\ninvestigated by adopting an off-shell form factor in the Regge model which\nbetter describes the observed energy dependence of sigmaT and sigmaL.", + "category": "nucl-ex" + }, + { + "text": "Proton Capture on ^{17}O and its astrophysical implications: The reaction $^{17}$O$(p,\\gamma)^{18}$F influences hydrogen-burning\nnucleosynthesis in several stellar sites, such as red giants, asymptotic giant\nbranch (AGB) stars, massive stars and classical novae. In the relevant\ntemperature range for these environments ($T_{9}=0.01-0.4), the main\ncontributions to the rate of this reaction are the direct capture process, two\nlow lying narrow resonances ($E_{r}=65.1$ and 183 keV) and the low-energy tails\nof two broad resonances ($E_{r}=557$ and 677 keV). Previous measurements and\ncalculations give contradictory results for the direct capture contribution\nwhich in turn increases the uncertainty of the reaction rate. In addition, very\nfew published cross section data exist for the high energy region that might\naffect the interpretation of the direct capture and the contributions of the\nbroad resonances in the lower energy range. This work aims to address these\nissues. The reaction cross section was measured in a wide proton energy range\n($E_{c.m.}=345$ - 1700 keV) and at several angles\n($\\theta_{lab}=0^{\\circ},45^{\\circ},90^{\\circ},135^{\\circ}$). The observed\nprimary $\\gamma$-transitions were used as input in an $R$-matrix code in order\nto obtain the contribution of the direct capture and the two broad resonances\nto the low-energy region. The extrapolated S-factor from the present data is in\ngood agreement with the existing literature data in the low-energy region. A\nnew reaction rate was calculated from the combined results of this work and\nliterature S-factor determinations. Resonance strengths and branchings are\nreported for several $^{18}$F states. We were able to extrapolate the\nastrophysical S-factor of the reaction $^{17}$O$(p,\\gamma)^{18}$F at low\nenergies from cross section data taken at higher energies. No significant\nchanges in the nucleosynthesis are expected from the newly calculated reaction\nrate.", + "category": "nucl-ex" + }, + { + "text": "Coherent J/psi photoproduction in ultra-peripheral PbPb collisions at\n sqrt(s[NN]) = 2.76 TeV with the CMS experiment: The cross section for coherent J/psi photoproduction accompanied by at least\none neutron on one side of the interaction point and no neutron activity on the\nother side, X[n]0[n], is measured with the CMS experiment in ultra-peripheral\nPbPb collisions at sqrt(s[NN]) = 2.76 TeV. The analysis is based on a data\nsample corresponding to an integrated luminosity of 159 inverse microbarns,\ncollected during the 2011 PbPb run. The J/psi mesons are reconstructed in the\ndimuon decay channel, while neutrons are detected using zero degree\ncalorimeters. The measured cross section is dsigma[coh,X[n]0[n]] / dy(J/psi) =\n0.36 +/- 0.04 (stat) +/- 0.04 (syst) mb in the rapidity interval 1.8 < abs(y) <\n2.3. Using a model for the relative rate of coherent photoproduction processes,\nthis X[z,n,z] measurement gives a total coherent photoproduction cross section\nof dsigma[coh] / dy(J/psi) = 1.82 +/- 0.22 (stat) +/- 0.20 (syst) +/- 0.19\n(theo) mb. The data strongly disfavour the impulse approximation model\nprediction, indicating that nuclear effects are needed to describe coherent\nJ/psi photoproduction in gamma + Pb interactions. The data are found to be\nconsistent with the leading twist approximation, which includes nuclear gluon\nshadowing.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the complete nuclide production and kinetic energies of\n the system 136Xe + hydrogen at 1 GeV per nucleon: We present an extensive overview of production cross sections and kinetic\nenergies for the complete set of nuclides formed in the spallation of 136Xe by\nprotons at the incident energy of 1 GeV per nucleon. The measurement was\nperformed in inverse kinematics at the FRagment Separator (GSI, Darmstadt).\nSlightly below the Businaro-Gallone point, 136Xe is the stable nuclide with the\nlargest neutron excess. The kinematic data and cross sections collected in this\nwork for the full nuclide production are a general benchmark for modelling the\nspallation process in a neutron-rich nuclear system, where fission is\ncharacterised by predominantly mass-asymmetric splits.", + "category": "nucl-ex" + }, + { + "text": "Performance of scintillation materials at cryogenic temperatures: An increasing number of applications of scintillators at low temperatures,\nparticularly in cryogenic experiments searching for rare events, has motivated\nthe investigation of scintillation properties of materials over a wide\ntemperature range. This paper provides an overview of the latest results on the\nstudy of luminescence, absorption and scintillation properties of materials\nselected for rare event searches so far. These include CaWO4, ZnWO4, CdWO4,\nMgWO4, CaMoO4, CdMoO4, Bi4Ge3O12, CaF2, MgF2, ZnSe and AL2O3-Ti. We discuss the\nprogress achieved in research and development of these scintillators, both in\nmaterial preparation and in the understanding of scintillation mechanisms, as\nwell as the underlying physics. To understand the origin of the performance\nlimitation of self-activated scintillators we employed a semi-empirical model\nof conversion of high energy radiation into light and made appropriate\nprovision for effects of temperature and energy transfer. We conclude that the\nlow-temperature value of the light yield of some modern scintillators, namely\nCaWO4, CdWO4 and Bi4Ge3O12, is close to the theoretical limit. Finally, we\ndiscuss the advantages and limitations of different materials with emphasis on\ntheir application as cryogenic phonon-scintillation detectors (CPSD) in rare\nevent search experiments.", + "category": "nucl-ex" + }, + { + "text": "Quenching of $g_{\\rm A}$ deduced from the $\u03b2$-spectrum shape of\n $^{113}$Cd measured with the COBRA experiment: A dedicated study of the quenching of the weak axial-vector coupling strength\n$g_{\\rm A}$ in nuclear processes has been performed by the COBRA collaboration.\nThis investigation is driven by nuclear model calculations which show that the\n$\\beta$-spectrum shape of the fourfold forbidden non-unique decay of $^{113}$Cd\nstrongly depends on the effective value of $g_{\\rm A}$. Using an array of\nCdZnTe semiconductor detectors, 45 independent $^{113}$Cd spectra were obtained\nand interpreted in the context of three nuclear models. The resulting effective\nmean values are $\\bar{g}_{\\rm A}(\\text{ISM}) = 0.915 \\pm 0.007$, $\\bar{g}_{\\rm\nA}(\\text{MQPM}) = 0.911 \\pm 0.013$ and $\\bar{g}_{\\rm A}(\\text{IBFM-2}) = 0.955\n\\pm 0.022$. These values agree well within the determined uncertainties and\ndeviate significantly from the free value of $g_{\\rm A}$. This can be seen as a\nfirst step towards answering the long-standing question regarding quenching\neffects related to $g_{\\rm A}$ in low-energy nuclear processes.", + "category": "nucl-ex" + }, + { + "text": "Low-spin particle/hole-core excitations in $^{41,47,49}$Ca isotopes\n studied by cold-neutron capture reactions: We present recent results on the structure of the one-valence-particle\n$^{41}$Ca and $^{49}$Ca, and one-valence-hole $^{47}$Ca, nuclei. The isotopes\nof interest were populated via the cold-neutron capture reactions\n$^{40}$Ca(n,$\\gamma$), $^{48}$Ca(n,$\\gamma$) and $^{46}$Ca(n,$\\gamma$),\nrespectively. The experiments were performed at the Institut Laue-Langevin,\nwithin the EXILL campaign, which employed a large array of HPGe detectors. The\n$\\gamma$ decay and level schemes of these nuclei were investigated by\n$\\gamma$-ray coincidence relationships, leading to the identification of 41,\n10, and 6 new transitions in $^{41}$Ca, $^{47}$Ca, and $^{49}$Ca, respectively.\nBranching ratios and intensities were extracted for the $\\gamma$ decay from\neach state, and $\\gamma$-ray angular correlations were performed to establish a\nnumber of transition multipolarities and mixing ratios, thus helping in the\nspin assignment of the states. The experimental findings are discussed along\nwith microscopic, self-consistent beyond-mean-field calculations performed with\nthe Hybrid Configuration Mixing model, based on a Skyrme SkX Hamiltonian. The\nlatter suggests that a fraction of the low-spin states of the $^{41}$Ca,\n$^{49}$Ca, and $^{47}$Ca nuclei is characterized by the coexistence of either\n2p-1h and 1p-2h excitations, or couplings between single-particle/hole degrees\nof freedom and collective vibrations (phonons) of the doubly-magic \"core\".", + "category": "nucl-ex" + }, + { + "text": "Evidence for the pair-breaking process in 116,117Sn: The nuclear level densities of 116,117Sn below the neutron separation energy\nhave been determined experimentally from the (3He,alpha gamma) and (3He,3He\ngamma') reactions, respectively. The level densities show a characteristic\nexponential increase and a difference in magnitude due to the odd-even effect\nof the nuclear systems. In addition, the level densities display pronounced\nstep-like structures that are interpreted as signatures of subsequent breaking\nof nucleon pairs.", + "category": "nucl-ex" + }, + { + "text": "Analysing powers and spin correlations in deuteron-proton charge\n exchange at 726 MeV: The charge exchange of vector polarised deuterons on a polarised hydrogen\ntarget has been studied in a high statistics experiment at the COSY-ANKE\nfacility at a deuteron beam energy of Td = 726 MeV. By selecting two fast\nprotons at low relative energy E_{pp}, the measured analysing powers and spin\ncorrelations are sensitive to interference terms between specific\nneutron-proton charge-exchange amplitudes at a neutron kinetic energy of Tn ~\n1/2 Td =363 MeV. An impulse approximation calculation, which takes into account\ncorrections due to the angular distribution in the diproton, describes\nreasonably the dependence of the data on both E_{pp} and the momentum transfer.\nThis lends broad support to the current neutron-proton partial-wave solution\nthat was used in the estimation.", + "category": "nucl-ex" + }, + { + "text": "Measurement of the nuclear modification factor for muons from charm and\n bottom hadrons in Pb+Pb collisions at 5.02 TeV with the ATLAS detector: Heavy-flavour hadron production provides information about the transport\nproperties and microscopic structure of the quark-gluon plasma created in\nultra-relativistic heavy-ion collisions. A measurement of the muons from\nsemileptonic decays of charm and bottom hadrons produced in Pb+Pb and $pp$\ncollisions at a nucleon-nucleon centre-of-mass energy of 5.02 TeV with the\nATLAS detector at the Large Hadron Collider is presented. The Pb+Pb data were\ncollected in 2015 and 2018 with sampled integrated luminosities of\n$208~\\mathrm{\\mu b}^{-1}$ and $38~\\mathrm{\\mu b^{-1}}$, respectively, and $pp$\ndata with a sampled integrated luminosity of $1.17~\\mathrm{pb}^{-1}$ were\ncollected in 2017. Muons from heavy-flavour semileptonic decays are separated\nfrom the light-flavour hadronic background using the momentum imbalance between\nthe inner detector and muon spectrometer measurements, and muons originating\nfrom charm and bottom decays are further separated via the muon track's\ntransverse impact parameter. Differential yields in Pb+Pb collisions and\ndifferential cross sections in $pp$ collisions for such muons are measured as a\nfunction of muon transverse momentum from 4 GeV to 30 GeV in the absolute\npseudorapidity interval $|\\eta| < 2$. Nuclear modification factors for charm\nand bottom muons are presented as a function of muon transverse momentum in\nintervals of Pb+Pb collision centrality. The measured nuclear modification\nfactors quantify a significant suppression of the yields of muons from decays\nof charm and bottom hadrons, with stronger effects for muons from charm hadron\ndecays.", + "category": "nucl-ex" + }, + { + "text": "Plans for a Neutron EDM Experiment at SNS: The electric dipole moment of the neutron, leptons, and atoms provide a\nunique window to Physics Beyond the Standard Model. We are currently developing\na new neutron EDM experiment (the nEDM Experiment). This experiment, which will\nbe run at the 8.9 A Neutron Line at the Fundamental Neutron Physics Beamline\n(FNPB) at the Spallation Neutron Source (SNS) at the Oak Ridge National\nLaboratory, will search for the neutron EDM with a sensitivity two orders of\nmagnitude better than the present limit. In this paper, the motivation for the\nexperiment, the experimental method, and the present status of the experiment\nare discussed.", + "category": "nucl-ex" + }, + { + "text": "$J/\u03c8$ and $\u03a5$ measurements in STAR: Heavy-quarkonium states are expected to evidenciate the deconfinement of the\nnuclear matter into a Quark-Gluon Plasma in heavy-ion collisions. To strive\nconclusive information from quarkonium production modification in A+A\ncollisions, systematic measurements of the $J/\\psi$ and $\\Upsilon$ states in\np+p, d+Au and Au+Au collisions are necessary. To accomplish this mission the\nSTAR experiment has a Quarkonium program based on the development of specific\ntrigger setups that take advantage of the large STAR acceptance. In this work\nwe present the preliminary results of the $J/\\psi$ and $\\Upsilon$ measurement\nin 200 GeV p+p and the first measurements of $\\Upsilon$ in 200 GeV heavy ion\ncollisions.", + "category": "nucl-ex" + }, + { + "text": "New developments in the experimental data for charged particle\n production of medical radioisotopes: The goal of the present work is to give a review of developments achieved\nexperimentally in the field of nuclear data for medically important\nradioisotopes in the last three years. The availability and precision of\nproduction related nuclear data is continuously improved mainly experimentally.\nThis review emphasizes a couple of larger fields: the Mo/Tc generator problem\nand the generator isotopes in general, heavy alpha-emitters and the rare-earth\nelements. Other results in the field of medical radioisotope production are\nalso listed.", + "category": "nucl-ex" + }, + { + "text": "Background Studies for the Neutral Current Detector Array in the Sudbury\n Neutrino Observatory: An array of 3He-filled proportional counters will be used in the Sudbury\nNeutrino Observatory to measure the neutral-current interaction of neutrinos\nand deuterium. We describe the backgrounds to this detection method.", + "category": "nucl-ex" + }, + { + "text": "Nuclear Muon Capture in Hydrogen and its Interplay with Muon Atomic\n Physics: The singlet capture rate $\\Lambda_S$ for the semileptonic weak process $\\mu+p\n\\to n+\\nu_\\mu$ has been measured in the MuCap experiment. The novel\nexperimental technique is based on stopping muons in an active target,\nconsisting of a time projection chamber operating with ultra-pure hydrogen.\nThis allows the unambiguous determination of the pseudoscalar form factor $g_P$\nof the charged electroweak current of the nucleon. Our first result\n$g_P(q^2=-0.88 m^2_\\mu) = 7.3 \\pm 1.1 $ is consistent with accurate theoretical\npredictions and constitutes an important test of QCD symmetries. Additional\ndata are being collected with the aim of a three-fold reduction of the\nexperimental uncertainties. Building on the developed advanced techniques, the\nnew MuSun experiment is being planned to measure the muon capture rate on the\ndeuteron to 1.5% precision. This would provide the by far most accurate\nexperimental information on the axial current interacting with the two-nucleon\nsystem and determine the low energy constant $L_{1A}$ relevant for solar\nneutrino reactions.\n Muon induced atomic and molecular processes represent challenges as well as\nopportunities for this science program, and their interplay with the main\nnuclear and weak-interaction physics aspects will be discussed.", + "category": "nucl-ex" + }, + { + "text": "Virtual Compton Scattering and Neutral Pion Electroproduction in the\n Resonance Region up to the Deep Inelastic Region at Backward Angles: We have made the first measurements of the virtual Compton scattering (VCS)\nprocess via the H$(e,e'p)\\gamma$ exclusive reaction in the nucleon resonance\nregion, at backward angles. Results are presented for the $W$-dependence at\nfixed $Q^2=1$ GeV$^2$, and for the $Q^2$-dependence at fixed $W$ near 1.5 GeV.\nThe VCS data show resonant structures in the first and second resonance\nregions. The observed $Q^2$-dependence is smooth. The measured ratio of\nH$(e,e'p)\\gamma$ to H$(e,e'p)\\pi^0$ cross sections emphasizes the different\nsensitivity of these two reactions to the various nucleon resonances. Finally,\nwhen compared to Real Compton Scattering (RCS) at high energy and large angles,\nour VCS data at the highest $W$ (1.8-1.9 GeV) show a striking $Q^2$-\nindependence, which may suggest a transition to a perturbative scattering\nmechanism at the quark level.", + "category": "nucl-ex" + }, + { + "text": "Investigation of $\u03b2\u03b2$ decay in $^{150}$Nd and $^{148}$Nd to the\n excited states of daughter nuclei: Double beta decay of $^{150}$Nd and $^{148}$Nd to the excited states of\ndaughter nuclei have been studied using a 400 cm$^3$ low-background HPGe\ndetector and an external source consisting of 3046 g of natural Nd$_2$O$_3$\npowder. The half-life for the two-neutrino double beta decay of $^{150}$Nd to\nthe excited 0$^+_1$ state in $^{150}$Sm is measured to be\n$T_{1/2}=[1.33^{+0.36}_{-0.23}(stat)^{+0.27}_{-0.13}(syst)]\\cdot 10^{20}$ y.\nFor other $(0\\nu + 2\\nu)$ transitions to the 2$^+_1$, 2$^+_2$, 2$^+_3$, and\n0$^+_2$ levels in $^{150}$Sm, limits are obtained at the level of $\\sim\n(2-8)\\cdot 10^{20}$ y. In the case of $^{148}$Nd only limits for the $(0\\nu +\n2\\nu)$ transitions to the 2$^+_1$, 0$^+_1$, and 2$^+_2$ excited states in\n$^{148}$Sm were obtained and are at the level of \\sim (4-8)\\cdot 10^{20}$ y.", + "category": "nucl-ex" + }, + { + "text": "Energy dependence of identified hadron spectra and event-by-event\n fluctuations in p+p interactions from NA61/SHINE at the CERN SPS: NA61/SHINE at the CERN SPS is a fixed-target experiment pursuing a rich\nphysics program including measurements for heavy ion, neutrino and cosmic ray\nphysics. The main goal of the ion program is to explore the most interesting\n$T, mu_{B}$ region of the phase diagram of strongly interacting matter. We plan\nto study the properties of the onset of deconfinement and to search for the\nsignatures of the critical point. The search is performed by varying collision\nenergy (13A-158A GeV/c) and system size (p+p, Be+Be, Ar+Ca, Xe+La).\n Thanks to its large acceptance and excellent particle identification\ncapability NA61/SHINE is well suited for performing high-precision particle\nproduction measurements as well as for studying event-by-event fluctuations in\np+p, p+nucleus and nucleus+nucleus collisions.\n Preliminary results on p+p interactions at 20, 31, 40, 80 and 158 GeV/c are\npresented. They include inclusive spectra of pi+, pi-, K- and protons as a\nfunction of transverse momentum/mass and rapidity as well as event-by-event\nfluctuations of transverse momentum, azimuthal angle and chemical composition.\nThe new NA61 measurements are compared with the corresponding results of NA49\non central Pb+Pb collisions and with predictions of Monte Carlo models.\n Finally, the future plans of NA61/SHINE are summarised.", + "category": "nucl-ex" + }, + { + "text": "System size dependence of freeze-out properties at RHIC: The STAR experiment at RHIC has measured identified pi(+/-), K(+/-) and\np(pbar) spectra and ratios from sqrt(s_NN) = 62.4 and 200 GeV Cu+Cu collisions.\nThe new Cu+Cu results are studied with hydro-motivated blast-wave and\nstatistical model frameworks in order to characterize the freeze-out properties\nof this system. Along with measurements from Au+Au and p+p collisions, the\nobtained freeze-out parameters are discussed as a function of collision energy,\nsystem size, centrality and inferred energy density. This multi-dimensional\nsystematic study reveals the importance of the collision geometry and furthers\nour understanding of the QCD phases.", + "category": "nucl-ex" + }, + { + "text": "Multifragmentation in Collisions of 4.4gev-Deuterons with Gold Target: The relative velocity correlation function of pairs of intermediate mass\nfragments has been studied for d+Au collitions at 4.4 GeV. Experimental\ncorrelation functions are compared to that obtained by multibody Coulomb\ntrajectory calculations under the assumption of various decay timees of the\nfragmenting system. The combined approach with the empirically modified\nintranuclear cascade code followed by the statistical multifragmentation model\nwas used to generate the starting conditions for these calculations. The\nfragment emossion time is found to be less than 40 fm/c.", + "category": "nucl-ex" + }, + { + "text": "Nuclear Moments of Germanium Isotopes around $N$ = 40: Collinear laser spectroscopy measurements were performed on $^{69,71,73}$Ge\nisotopes ($Z = 32$) at ISOLDE-CERN. The hyperfine structure of the $4s^2 4p^2\n\\, ^3P_1 \\rightarrow 4s^2 4p 5s \\, ^3P_1^o$ transition of the germanium atom\nwas probed with laser light of 269 nm, produced by combining the\nfrequency-mixing and frequency-doubling techniques. The hyperfine fields for\nboth atomic levels were calculated using state-of-the-art atomic relativistic\nFock-space coupled-cluster calculations. A new $^{73}$Ge quadrupole moment was\ndetermined from these calculations and previously measured precision hyperfine\nparameters, yielding $Q_{\\rm s}$ = $-$0.198(4) b, in excellent agreement with\nthe literature value from molecular calculations. The moments of $^{69}$Ge have\nbeen revised: $\\mu$ = +0.920(5) $\\mu_{N}$ and $Q_{\\rm s}$= +0.114(8) b, and\nthose of $^{71}$Ge have been confirmed. The experimental moments around $N =\n40$ are interpreted with large-scale shell-model calculations using the JUN45\ninteraction, revealing rather mixed wave function configurations, although\ntheir $g$-factors are lying close to the effective single-particle values.\nThrough a comparison with neighboring isotones, the structural change from the\nsingle-particle nature of nickel to deformation in germanium is further\ninvestigated around $N = 40$.", + "category": "nucl-ex" + }, + { + "text": "Study of $J/\u03c8$ production and cold nuclear matter effects in $p$Pb\n collisions at $\\sqrt{s_{NN}}=5 \\mathrm{TeV}$: The production of $J/\\psi$ mesons with rapidity $1.5