Wed·Aug 7, 2019Wednesday·August 7, 2019

1. 01*

   Multiplicity dependence of (multi-)strange hadron production in proton-proton collisions at $\sqrt{s}$ = 13 TeV

   ALICE Collaboration

   The production rates and the transverse momentum distribution of strange hadrons at mid-rapidity ($|y|<0.5$) are measured in proton-proton collisions at $\sqrt{s}$ = 13 TeV as a function of the charged particle multiplicity, using the ALICE detector at the LHC. The production rates of ${\mathrm{K}}_{\mathrm{S}}^0$, $\Lambda$, $\Xi$, and $\Omega$ increase with the multiplicity faster than what is reported for inclusive charged particles. The increase is found to be more pronounced for hadrons with a larger strangeness content. Possible auto-correlations between the charged particles and the strange hadrons are evaluated by measuring the event-activity with charged particle multiplicity estimators covering different pseudorapidity regions. When comparing to lower energy results, the yields of strange hadrons are found to depend only on the mid-rapidity charged particle multiplicity. Several features of the data are reproduced qualitatively by general purpose QCD Monte Carlo models that take into account the effect of densely-packed QCD strings in high multiplicity collisions. However, none of the tested models reproduce the data quantitatively. This work corroborates and extends the ALICE findings on strangeness production in proton-proton collisions at 7 TeV.

   nucl-exhep-exEPJC(2020)·185 citations
2. 02*

   Neutron quadrupole transition strength in ${}^{10}$C deduced from the ${}^{10}$C$(\alpha ,{\alpha }^{\prime })$ measurement with the MAIKo active target

   T. Furuno · T. Kawabata🇯🇵 · S. Adachi · Y. Ayyad🇯🇵 · Y. Kanada-En'yo🇯🇵 · Y. Fujikawa🇯🇵 · K. Inaba🇯🇵 · M. Murata · H. J. Ong🇯🇵 · M. Sferrazza🇧🇪 · Y. Takahashi · T. Takeda🇯🇵 and 3 other authors

   Elastic and inelastic alpha scatterings on ${}^{10}$C were measured using a 68-MeV/u radioactive ${}^{10}$C beam incident on the recently developed MAIKo active target system. The phenomenological effective $\alpha$-$N$ interaction and the point-nucleon density distribution in the ground state were determined from the elastic scattering data. The cross sections of the inelastic alpha scattering were calculated using this interaction and density distribution and were compared with the experiment to determine the neutron quadrupole transition matrix element $M_n$ between the ground state and the $2_1^{+}$ state at $E_x=3.35$ MeV in ${}^{10}$C. The deduced neutron transition matrix element is $M_n=6.9\pm 0.7(\mathrm{fit})\pm 1.2(\mathrm{sys})$ fm${}^2$. The ratio of the neutron transition strength to proton transition strength was determined as $M_n/M_p=1.05\pm 0.11(\mathrm{fit})\pm 0.17(\mathrm{sys})$, which indicates that the quadrupole transition between the ground state and the $2_1^{+}$ state in ${}^{10}$C is less neutron dominant compared to that in ${}^{16}$C.

   nucl-exPRC(2019)·13 citations
3. 03*

   Excited states of the odd-odd nucleus 158Eu from the (d,alpha) reaction

   D. Bucurescu🇷🇴 · S. Pascu🇷🇴 · T. Faestermann🇩🇪 · H-F. Wirth🇩🇪 · C. Costache🇷🇴 · A. Ionescu🇷🇴 · R. Lica🇷🇴 · R. Mihai · A. Turturica🇷🇴 · R. Hertenberger🇩🇪

   Excited states in the 158Eu nucleus have been determined with the 160Gd(d, alpha)158Eu reaction, studied at an incident energy of 18.0 MeV with the Munich tandem and the Q3D spectrograph. More than 50 excited states have been determined up to 1.6 MeV excitation, some of them corresponding to states previously observed in the beta-decay of 158Sm. The number of levels found in this nucleus at low excitation energies follows the systematic trend of the level densities in the other isotopes with mass 152-156.

   nucl-exPRC(2019)·0 citations
4. 04*

   Measurement of the cross sections for inclusive electron scattering in the E12-14-012 experiment at Jefferson Lab

   M. Murphy🇺🇸 · H. Dai🇺🇸 · L. Gu🇺🇸 · D. Abrams🇺🇸 · A. M. Ankowski🇺🇸 · B. Aljawrneh🇺🇸 · S. Alsalmi🇺🇸 · J. Bane🇺🇸 · S. Barcus🇺🇸 · O. Benhar🇮🇹 · V. Bellini🇮🇹 · J. Bericic🇺🇸 and 47 other authors

   The E12-14-012 experiment performed at Jefferson Lab Hall A has collected inclusive electron-scattering data for different targets at the kinematics corresponding to beam energy 2.222 GeV and scattering angle 15.54 deg. Here we present a comprehensive analysis of the collected data and compare the double-differential cross sections for inclusive scattering of electrons, extracted using solid targets (aluminum, carbon, and titanium) and a closed argon-gas cell. The data extend over broad range of energy transfer, where quasielastic interaction, Delta-resonance excitation, and inelastic scattering yield contributions to the cross section. The double-differential cross sections are reported with high precision (~3%) for all targets over the covered kinematic range.

   ↳ hep-exhep-phnucl-exPRC(2019)·30 citations
5. 05*

   Nucleon spin polarization in intermediate-energy heavy-ion collisions

   Yin Xia🇨🇳 · Jun Xu🇨🇳

   Based on a spin-dependent Boltzmann-Uehling-Uhlenbeck transport model with spin-dependent potentials incorporated using the lattice Hamiltonian method, we have studied the global spin polarization perpendicular to the reaction plane as well as the local spin polarization in the longitudinal direction in non-central intermediate-energy heavy-ion collisions, as an extension of similar studies in relativistic heavy-ion collisions. Both the global and the local spin polarizations are found to be mostly dominated by the time-odd component of the nuclear spin-orbit potential. Impacts of various theoretical uncertainties on the nucleon spin polarization as well as its dependence on the beam energy and impact parameter are discussed. Our study serves as a baseline for understanding the spin polarization mechanism of strongly interacting matter produced in heavy-ion collisions dominated by nucleon degree of freedom.

   ↳ nucl-thhep-exnucl-exPLB(2020)·8 citations
6. 06*

   Neutron valence structure from nuclear deep inelastic scattering

   E.P. Segarra🇺🇸 · A. Schmidt🇺🇸 · T. Kutz🇺🇸 · D.W. Higinbotham🇺🇸 · E. Piasetzky🇮🇱 · M. Strikman🇺🇸 · L.B. Weinstein🇺🇸 · O. Hen🇺🇸

   Mechanisms of spin-flavor SU(6) symmetry breaking in Quantum Chromodynamics (QCD) are studied via an extraction of the free neutron structure function from a global analysis of deep inelastic scattering (DIS) data on the proton and on nuclei from $A=2$ (deuterium) to 208 (lead). Modification of the structure function of nucleons bound in atomic nuclei (known as the EMC effect) are consistently accounted for within the framework of a universal modification of nucleons in short-range correlated (SRC) pairs. Our extracted neutron-to-proton structure function ratio $F_2^n/F_2^p$ becomes constant for $x_B\ge 0.6$, equalling $0.47\pm 0.04$ as $x_B\to 1$, in agreement with theoretical predictions of perturbative QCD and the Dyson Schwinger equation, and in disagreement with predictions of the Scalar Diquark dominance model. We also predict $F_2^{{}^3\mathrm{He}}/F_2^{{}^3\mathrm{H}}$, recently measured, yet unpublished, by the MARATHON collaboration, the nuclear correction function that is needed to extract $F_2^n/F_2^p$ from $F_2^{{}^3\mathrm{He}}/F_2^{{}^3\mathrm{H}}$, and the theoretical uncertainty associated with this extraction.

   ↳ nucl-thhep-exhep-phnucl-exPRL(2020)·43 citations

* Reconstructed cohort: no mailing for this day survives in the archive. Papers are grouped by their submission times and arXiv's announcement cut-off, assuming announcement without delay; positions follow identifier order. Validated at ~91% exact-day agreement against the archived era.