Mon·Apr 18, 2022Monday·April 18, 2022

1. 01*

   Cumulants of conserved charges in hydrodynamic simulations

   Renan Hirayama🇩🇪 · Frederique Grassi🇧🇷 · Willian Matioli Serenone🇧🇷 · Jean-Yves Ollitrault🇫🇷

   We introduce a fast and simple method of computing cumulants of net-proton or net-charge fluctuations in event-by-event hydrodynamic simulations of heavy-ion collisions. One evaluates the mean numbers of particles in every hydrodynamic event. Cumulants are then expressed as a function of these mean numbers. We implement the corrections due to global conservation laws. The method is tested using ideal hydrodynamic simulations of Au+Au collisions at $\sqrt{s_{NN}}=200$ AGeV with the NeXSPheRIO code. Results are in good agreement with experimental data on net-proton and net-charge fluctuations by the STAR collaboration.

   ↳ nucl-thhep-exhep-phnucl-exPRC(2023)·5 citations
2. 02*

   Peeling away neutron skin in ultracentral collisions of relativistic nuclei

   Nikita Kozyrev (1 and 2) · Aleksandr Svetlichnyi (1 and 2) · Roman Nepeivoda (1 and 2) · Igor Pshenichnov (1 and 2) ((1) Moscow Institute of Physics and Technology, Dolgoprudny, Russia, (2) Institute for Nuclear Research, Russian Academy of Sciences, Moscow, Russia)🇷🇺

   In heavy nuclei the ratio between local densities of neutrons and protons increases towards the nuclear periphery. The excess of neutrons is known as the neutron skin (NS) with a subtle difference ($<0.5$~fm) between the r.m.s radii of the distributions of neutrons and protons. We show that the presence of NS in ${}^{208}$Pb leads to extra spectator neutrons in ultracentral ${}^{208}$Pb--${}^{208}$Pb collisions at the CERN SPS and LHC. The yields of spectator neutrons and protons were calculated within a new version of Abrasion-Ablation Monte Carlo for Colliders model (AAMCC-MST) taking into account NS and pre-equilibrium clustering of spectator matter. While the average numbers of spectator neutrons and protons in ultracentral collisions vary insignificantly, the cross sections of emission of certain numbers of spectator neutrons in events with 0,1,...5 spectator protons are changed by 50--250\%, depending on the thickness of NS. These cross sections are less sensitive to other parameters in calculations, and their measurements in the ALICE experiment at the LHC will make it possible to restrict the existing variety of neutron density parameterizations in ${}^{208}$Pb.

   ↳ nucl-thnucl-exEPJA(2022)·9 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.