The hadronic nucleus-nucleus cross section and the nucleon size

Abstract

Even though the total hadronic nucleus-nucleus cross section is among the most fundamental observables, it has only recently been measured precisely for lead-lead collisions at the LHC. This measurement implies the nucleon width should be below 0.7 fm, which is in contradiction with all known state-of-the-art Bayesian estimates. We study the implications of the smaller nucleon width on quark-gluon plasma properties such as the bulk viscosity. The smaller nucleon width dramatically improves the description of several triple-differential observables.

Comments: 5 pages, 4 figures + Appendix. v2: added XeXe results. Trajectum can be downloaded at https://sites.google.com/view/govertnijs/trajectum, output files and plotting routines at http://wilkevanderschee.nl/