https://doi.org/10.1140/epja/s10050-022-00832-5
Regular Article - Theoretical Physics
Peeling away neutron skin in ultracentral collisions of relativistic nuclei
1
Moscow Institute of Physics and Technology, Institutskiy per. 9, 141701, Dolgoprudny, Moscow Region, Russia
2
Institute for Nuclear Research of the Russian Academy of Sciences, Prospekt 60-letiya Oktyabrya 7a, 117312, Moscow, Russia
Received:
15
April
2022
Accepted:
12
September
2022
Published online:
22
September
2022
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 (
fm) between the r.m.s radii of the distributions of neutrons and protons. We show that the presence of NS in 
Pb leads to extra spectator neutrons in ultracentral Pb–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 variety of neutron density parameterizations existing for Pb.
© The Author(s), under exclusive licence to Società Italiana di Fisica and Springer-Verlag GmbH Germany, part of Springer Nature 2022. Springer Nature or its licensor holds exclusive rights to this article under a publishing agreement with the author(s) or other rightsholder(s); author self-archiving of the accepted manuscript version of this article is solely governed by the terms of such publishing agreement and applicable law.
