Mass dependence of the deconfinement and chiral restoration critical temperatures in nonlocal SU(2) PNJL models

TL;DR

This study investigates how the critical temperatures for deconfinement and chiral restoration in nonlocal SU(2) PNJL models depend on quark mass, revealing a strong entanglement and linear growth consistent with lattice QCD, with early first-order transition onset.

Contribution

It introduces a nonlocal SU(2) PNJL model analysis of mass dependence, contrasting with local models and aligning with lattice QCD results.

Findings

Deconfinement and chiral transition temperatures are strongly entangled.

Critical temperatures increase linearly with pion mass.

Early onset of first-order transition at high quark masses.

Abstract

In the framework of nonlocal SU(2) chiral quark models with Polyakov loop, we analyze the dependence of the deconfinement and chiral restoration critical temperatures on the explicit chiral symmetry breaking driven by the current quark mass. Our results are compared with those obtained within the standard local Polyakov-Nambu-Jona-Lasinio (PNJL) model and with lattice QCD calculations. For a wide range of pion masses, it is found that both deconfinement and chiral restoration critical temperatures turn out to be strongly entangled, in contrast with the corresponding results within the PNJL model. In addition, it is seen that the growth of the critical temperatures with the pion mass above the physical point is basically linear, with a slope parameter which is close to the existing lattice QCD estimates. On the other hand, within the present mean field calculation we find an early onset of the first order transition expected in the large quark mass limit.