Baryon stopping as a signal of the mixed phase onset

TL;DR

The paper suggests that baryon stopping behavior, characterized by a zigzag pattern in the net-proton rapidity spectrum, signals the onset of a mixed phase in heavy-ion collisions, with models including phase transitions better reproducing this irregularity.

Contribution

It demonstrates that the irregularity in baryon stopping can serve as an indicator of the phase transition onset in nuclear matter.

Findings

Hadronic EoS fails to reproduce zigzag irregularity.

EoS with phase transition qualitatively reproduces the irregularity.

Baryon stopping irregularity signals mixed phase onset.

Abstract

It is argued that the experimentally observed baryon stopping indicates a non-monotonous behaviour as a function of the incident energy of colliding nuclei. This can be quantified by a midrapidity reduced curvature of the net-proton rapidity spectrum and reveals itself as a zigzag irregularity in the excitation function of this curvature. The three-fluid dynamic calculations with a hadronic equation of state (EoS) fail to reproduce this irregularity. At the same time, the same calculations with an EoS involving a first-order phase transition and a crossover one into the quark-gluon phase do reproduce this zigzag behaviour, however only qualitatively.