PNJL model at zero temperature: three-flavor case

TL;DR

This paper develops a three-flavor PNJL model at zero temperature, exploring phase transitions, chiral symmetry restoration, and applications to neutron star matter, revealing significant effects of the Polyakov loop on quark masses and phase structure.

Contribution

It introduces a three-flavor PNJL model with Polyakov loop dependence at zero temperature, analyzing phase transitions and neutron star implications.

Findings

Strong reduction of strange quark mass at deconfinement point

Polyakov loop promotes chiral symmetry restoration in strange quarks

Model predictions align with NICER neutron star data

Abstract

We propose a three-flavor version of the Polyakov-Nambu-Jona-Lasino (PNJL) model at zero temperature regime, by implementing a traced Polyakov loop ($\Phi$) dependence in the scalar, vector and 't Hooft channel strengths. We study the thermodynamics of this model, named as PNJL0, with special attention for the first order confinement/deconfinement phase transition for which $\Phi$ is the order parameter. For the symmetric quark matter case, an interesting feature observed is a strong reduction of the constituent strange quark mass ($M_s$) at the chemical potential related to point where deconfinement takes place. The emergence of $\Phi$ favors the restoration of chiral symmetry even for the strange quark. We also investigate the charge neutral system of quarks and leptons in weak equilibrium. As an application, we construct a hadron-quark phase transition with a density dependent hadronic model coupled to the SU(3) PNJL0 model. In this case, the quark side is composed by deconfined particles. This approach is used to determine mass-radius profiles compatible with recent data from the Neutron Star Interior Composition Explorer (NICER) mission.