Thermodynamics of a three-flavor nonlocal Polyakov--Nambu--Jona-Lasinio model

TL;DR

This paper extends a nonlocal PNJL model to three quark flavors, incorporating the U(1) axial anomaly, and studies its thermodynamics, phase transitions, and critical point behavior in the QCD phase diagram.

Contribution

It introduces a three-flavor nonlocal PNJL model with axial U(1) anomaly and compares its thermodynamics to lattice QCD results, including finite density analysis.

Findings

Model reproduces lattice QCD thermodynamics for 2+1 flavors.

Critical point location depends on axial U(1) anomaly strength.

Includes pionic and kaonic contributions to pressure.

Abstract

The present work generalizes a nonlocal version of the Polyakov loop-extended Nambu and Jona-Lasinio (PNJL) model to the case of three active quark flavors, with inclusion of the axial U(1) anomaly. Gluon dynamics is incorporated through a gluonic background field, expressed in terms of the Polyakov loop. The thermodynamics of the nonlocal PNJL model accounts for both chiral and deconfinement transitions. Our results obtained in mean-field approximation are compared to lattice QCD results for $N_\text{f}=2+1$ quark flavors. Additional pionic and kaonic contributions to the pressure are calculated in random phase approximation. Finally, this nonlocal 3-flavor PNJL model is applied to the finite density region of the QCD phase diagram. It is confirmed that the existence and location of a critical point in this phase diagram depends sensitively on the strength of the axial U(1) breaking interaction.