QCD phase transitions via a refined truncation of Dyson-Schwinger equations

TL;DR

This paper uses a refined Dyson-Schwinger equations approach to analyze QCD phase transitions, accurately locating the critical end point and proposing a generalized confinement criterion, with implications for heavy-ion collision experiments.

Contribution

It introduces a refined truncation scheme for Dyson-Schwinger equations to study QCD phase transitions and proposes a new confinement criterion, improving the understanding of the phase diagram.

Findings

The critical end point shifts to lower chemical potential and higher temperature in the refined scheme.

The chiral susceptibility criterion effectively determines the phase boundary and CEP.

The CEP is predicted to occur in matter generated by Au-Au collisions at 9-15 GeV.

Abstract

We investigate both the chiral and deconfinement phase transitions of QCD matter in a refined scheme of Dyson-Schwinger equations, which have been shown to be successful in giving the meson mass spectrum and matching the interaction with the results from ab initio computation. We verify the equivalence of the chiral susceptibility criterion with different definitions for the susceptibility and confirm that the chiral susceptibility criterion is efficient to fix not only the chiral phase boundary but also the critical end point (CEP), especially when one could not have the effective thermodynamical potential. We propose a generalized Schwinger function criterion for the confinement. We give the phase diagram of both phase transitions and show that in the refined scheme the position of the CEP shifts to lower chemical potential and higher temperature. Based on our calculation and previous results of the chemical freeze out conditions, we propose that the CEP locates in the states of the matter generated by the Au--Au collisions with $\sqrt{s_{NN}^{}}=9\sim15$ GeV.