The hadronic SU(3) Parity Doublet Model for Dense Matter, its extension to quarks and the strange equation of state

TL;DR

This paper introduces a chiral SU(3) parity doublet model for dense matter, extending it to include quarks and strange matter, and analyzes its phase structure, including chiral symmetry restoration and deconfinement transitions, with results consistent with lattice QCD data.

Contribution

The paper develops a comprehensive parity doublet model incorporating hyperons and quarks, and explores its phase diagram, including deconfinement and chiral transitions, aligning with lattice QCD results.

Findings

First-order phase transition with critical endpoints depending on chiral partner masses.

Model's deconfinement transition matches lattice data at zero chemical potential.

Phase diagram shows decoupling of chiral symmetry restoration and deconfinement.

Abstract

A chiral model is introduced that is based on the parity doublet formulation of chiral symmetry including hyperonic degrees of freedom. The phase structure of the model is determined. Depending on the masses of the chiral partners the transition to the chirally restored phase shows a first-order line with critical endpoints as function of chemical potential and temperature in additional to the standard liquid-gas phase transition of self-bound nuclear matter. We extend the parity doublet model to describe the deconfinement phase transition which is in quantitative agreement with lattice data at $\mu_B=0$. The phase diagram of the model is presented which shows a decoupling of chiral symmetry restoration and deconfinement. Loosening the constraint of strangeness conservation we also investigate the phase diagram at net strangeness density. We calculate the strangeness per baryon fraction and the baryon strangeness correlation factor, two quantities that are sensitive on deconfinement and that can be used to interpret lattice calculations.