On the QCD phase structure from effective models

TL;DR

This paper reviews recent theoretical progress in understanding the QCD phase diagram using effective models, focusing on chiral symmetry, confinement, and the effects of the axial anomaly and Polyakov loop.

Contribution

It analyzes the impact of sigma mass, axial anomaly, and Polyakov loop on the QCD phase structure within an effective linear sigma model with three light quark flavors.

Findings

Chiral transition sensitivity to sigma mass

Existence of a critical end point depends on model parameters

Polyakov loop modifies the phase diagram structure

Abstract

Some recent theoretical developments of the QCD phase diagram are summarized. Chiral symmetry restoration and the confinement/deconfinement transition at nonzero temperature and quark densities are analyzed in the framework of an effective linear sigma model with three light quark flavors. The sensitivity of the chiral transition as well as the existence of a critical end point in the phase diagram on the value of the sigma mass is explored. The influence of the axial anomaly on the chiral critical surface is addressed. Finally, the modifications by the inclusion of the Polyakov loop on the phase structure are investigated.