The three-flavor chiral phase structure in hot and dense QCD matter

TL;DR

This paper investigates the chiral phase structure of hot and dense QCD matter with three flavors, analyzing condensates, meson masses, and the effects of the axial anomaly, to understand phase transitions and critical points.

Contribution

It provides a detailed analysis of the three-flavor chiral phase diagram, including the influence of the axial U(1)_A anomaly and the sigma mass on phase transitions and critical end points.

Findings

The axial anomaly significantly affects meson masses and phase structure.

The position of the critical end point depends on the sigma meson mass.

The chiral critical surface varies with pion and kaon masses, influenced by the anomaly.

Abstract

Chiral symmetry restoration at nonzero temperature and quark densities are investigated in the framework of a linear sigma model with N_f=3 light quark flavors. After the derivation of the grand potential in mean-field approximation, the nonstrange and strange condensates, the in-medium masses of the scalar and pseudoscalar nonets are analyzed in hot and dense medium. The influence of the axial anomaly on the nonet masses and the isoscalar mixings on the pseudoscalar \eta-\eta' and scalar \sigma(600)-f_0(1370) complex are examined. The sensitivity of the chiral phase transition as well as the existence and location of a critical end point in the phase diagram on the value of the sigma mass is explored. The chiral critical surface with and without the influence of the axial U(1)_A anomaly is elaborated as a function of the pion and kaon masses for several values of the sigma mass.