Thermodynamical properties of strongly interacting matter in a model with explicit chiral symmetry breaking interactions

TL;DR

This paper investigates how explicit chiral symmetry breaking interactions influence the thermodynamical properties of strongly interacting matter, using an extended Nambu Jona Lasinio model and comparing results with lattice QCD data.

Contribution

It introduces a comprehensive model including explicit chiral symmetry breaking interactions up to a certain order, highlighting their importance in describing QCD thermodynamics.

Findings

ESB terms are crucial for the soft region in the speed of sound.

8-quark interactions significantly affect the thermodynamic observables.

Model results with Polyakov loop align well with lattice QCD data.

Abstract

We analyse the effects of the light and strange current quark masses on the phase diagram of QCD at finite temperature and vanishing baryonic chemical potential, computing the speed of sound, the trace anomaly of the energy momentum tensor and the fluctuations and correlations of the conserved charges associated to baryonic, electric and strangeness numbers. The framework is a known extension of the three flavor Nambu Jona Lasinio model, which includes the full set of explicit chiral symmetry breaking interactions (ESB) up to the same order in large $N_c$ counting as the 't Hooft flavor mixing terms and eight quark interactions. It is shown that the ESB terms are relevant for the description of a soft region in the system's speed of sound and overall slope behavior of the observables computed. At the same time the role of the 8q interactions gets highlighted. The model extension with the Polyakov loop is considered and the results are compared to lattice QCD data.