Sign Structure of Susceptibilities of Conserved Charges in the (2+1) Polyakov Quark Meson Model

TL;DR

This paper investigates the sign structure of conserved charge susceptibilities in a (2+1) flavor Polyakov Quark Meson model, revealing negative correlations that could be experimentally measured to locate the QCD transition and critical point.

Contribution

It provides a detailed analysis of susceptibilities up to fourth order in a QCD-like model, exploring scenarios with and without a critical point and identifying negative correlations in the hadron-quark transition regime.

Findings

Certain correlations turn negative in the transition regime.

Negative correlations persist deep into the hadronic phase.

These correlations can be measured in heavy ion collision experiments.

Abstract

The sign structure of correlations of conserved charges are investigated in a QCD like model: the (2+1) flavor Polyakov Quark Meson model. We compute all susceptibilities of the conserved charges on the $(\mu_{B}-T)$ plane up to fourth order and a few at higher order as well. By varying the mass of the sigma meson, we are able to study and compare scenarios with as well as without a critical point. In the hadron-quark transition regime we identify certain correlations that turn negative unlike expectation from ideal hadron resonance gas calculations. The striking feature being that these remain negative deep into the hadronic side and thus could be measured in experiments. Measurement of such quantities in heavy ion collision experiments can elucidate the location of the QCD transition curve and possibly the critical point.