Neutron skin and centrality classification in high-energy heavy-ion collisions at the LHC

Understand

The concept of centrality in high-energy nuclear collisions has recently become a subject of an active debate.

• In particular, the experimental methods to determine the centrality that have given reasonable results for many observables in high-energy lead-lead collisions at the LHC have led to surprising behaviour in the case of proton-lead collisions.
• In this letter, we discuss the possibility to calibrate the experimental determination of centrality by asymmetries caused by mutually different spatial distributions of protons and neutrons inside the nuclei --- a well-known phenomenon in nuclear physics known as the neutron-skin effect.