Debye mass at the QCD transition in the PNJL model

TL;DR

This paper investigates the Debye mass at the QCD transition using a PNJL model, highlighting the effects of confinement and chiral symmetry breaking on color-electric screening, and connecting nonperturbative quark distributions with lattice QCD data.

Contribution

It provides a nonperturbative calculation of the Debye mass incorporating confinement and chiral effects within the PNJL model, and links it to perturbative QCD and lattice results.

Findings

Screening mass is determined by nonperturbative quark distribution and running coupling.

Polyakov loop suppresses charge carriers below the transition temperature.

Dynamical quark mass further suppresses screening due to chiral symmetry breaking.

Abstract

We consider colour-electric screening as expressed by the quark contribution to the Debye mass calculated in a PNJL model with emphasis on confining and chiral symmetry breaking effects. We observe that the screening mass is entirely determined by the nonperturbative quark distribution function and temperature dependent QCD running coupling. The role of the gluon background (Polyakov loop) is to provide strong suppression of the number of charge carriers below the transition temperature, as an effect of confinement, while the temperature dependent dynamical quark mass contributes additional suppression, as an effect of chiral symmetry breaking. An alternative derivation of this result from a modified kinetic theory is given, which allows for a slight generalization and explicit contact with perturbative QCD. This gives the possibility to gain insights into the colour screening mechanism in the region near the QCD pseudocritical temperature and to provide a guideline for the interpretation of lattice QCD data.