An effective chiral Hadron-Quark Equation of State Part I: Zero baryochemical potential

TL;DR

This paper develops an effective QCD equation of state model that captures chiral symmetry restoration and deconfinement, aligning qualitatively with lattice data at zero baryochemical potential.

Contribution

It introduces a unified model incorporating both hadronic and quark degrees of freedom with correct asymptotic behavior, advancing understanding of QCD phase transitions.

Findings

Model exhibits rapid crossover for order parameters

Thermodynamic quantities agree qualitatively with lattice data

Quantitative differences due to hadronic contributions

Abstract

We construct an effective model for the QCD equation of state, taking into account chiral symmetry restoration as well as the deconfinement phase transition. The correct asymptotic degrees of freedom at the high and low temperature limits are included (quarks $\leftrightarrow$ hadrons). The model shows a rapid crossover for both order parameters, as is expected from lattice calculations. We then investigate the thermodynamic properties of the model at $\mu_B=0$. All thermodynamic quantities are in qualitative agreement with lattice data, while apparent quantitative differences can be attributed to hadronic contributions and excluded volume corrections.