Phase diagram and isentropic curves from the vector meson extended Polyakov quark meson model

TL;DR

This paper explores the QCD phase diagram using an extended Polyakov quark meson model with vector mesons, determining phase boundaries, the critical end point, and isentropic curves, showing good agreement with lattice results.

Contribution

It introduces a detailed parameterization and hybrid approximation approach to study the phase diagram and thermodynamics of QCD within an extended meson model.

Findings

Identified the phase boundary and critical end point in the QCD phase diagram.

Calculated isentropic curves that match lattice QCD results in the crossover region.

Provided thermodynamic quantities consistent with known QCD behavior.

Abstract

In the framework of the $N_f = 2+1$ flavor (axial)vector meson extended Polyakov quark meson model we investigate the QCD phase diagram at finite temperature and density. We use a $\chi^2$ minimization procedure to parameterize the model based on tree\,-\,level decay widths and vacuum scalar and pseudoscalar curvature masses which incorporate the contribution of the constituent quarks. Using a hybrid approximation (mesons at tree level, fermions at one\,-\,loop level) for the grand potential we determine the phase boundary both on the $\mu_B-T$ and $\rho-T$ planes. We also determine the location of the critical end point of the phase diagram. Moreover by calculating the pressure and other thermodynamical quantities derived from it, we determine a set of isentropic curves in the crossover region. We show that the curves behave very similarly as their counterparts obtained from the lattice in the crossover regime.