Charge fluctuations in chiral models and the QCD phase transition

TL;DR

This paper investigates how charge fluctuations, especially higher cumulants of net-quark number density, can serve as sensitive probes of the chiral phase transition in QCD, using an extended chiral quark-meson model beyond mean-field.

Contribution

It introduces a functional renormalisation group analysis of the Polyakov loop-extended chiral model, highlighting the sensitivity of higher cumulants to the chiral crossover transition.

Findings

Higher order cumulants increase sharply near the transition

Net-quark number fluctuations are sensitive to chiral symmetry breaking

Results are relevant for heavy-ion collision experiments at RHIC and LHC

Abstract

We consider the Polyakov loop-extended two flavor chiral quark--meson model and discuss critical phenomena related with the spontaneous breaking of the chiral symmetry. The model is explored beyond the mean-field approximation in the framework of the functional renormalisation group. We discuss properties of the net-quark number density fluctuations as well as their higher cumulants. We show that with the increasing net-quark number density, the higher order cumulants exhibit a strong sensitivity to the chiral crossover transition. We discuss their role as probes of the chiral phase transition in heavy-ion collisions at RHIC and LHC.