Aspects of the phase diagram in (P)NJL-like models

TL;DR

This paper explores various aspects of the QCD phase diagram using NJL and PNJL models, including mesonic correlations, phase boundary reconstruction, and the critical surface in a three-flavor model.

Contribution

It presents new insights into the phase diagram by analyzing mesonic effects, reconstructing phase boundaries from susceptibility expansions, and demonstrating the non-standard critical surface scenario.

Findings

Mesonic correlations significantly affect the pressure near the phase transition.

The reconstructed phase boundary from Taylor expansion closely matches the exact boundary.

The non-standard critical surface scenario is realized in a three-flavor PNJL model with a μ-dependent interaction.

Abstract

We discuss three applications of NJL- and PNJL-like models to assess aspects of the QCD phase diagram: First, we study the effect of mesonic correlations on the pressure below and above the finite temperature phase transition within a nonlocal PNJL model beyond the mean-field approximation. Second, we reconstruct the phase boundary of an NJL model from a Taylor expansion of the chiral susceptibility about $\mu = 0$ and compare the result with the exact phase boundary. Finally, we demonstrate the realization of the "non-standard scenario" for the critical surface in a three-flavor PNJL model with a $\mu$-dependent determinant interaction.