The (magnetized) effective QCD phase diagram

TL;DR

This paper investigates the QCD phase diagram using a linear sigma model with quarks, identifying the critical end point's location and emphasizing the importance of plasma screening effects over confinement in this context.

Contribution

The study introduces a method to locate the critical end point in the QCD phase diagram using the linear sigma model with plasma screening effects, aligning with lattice calculations.

Findings

Critical end point located at (1.2, 0.8) in scaled units.

Plasma screening effects are crucial for determining the CEP location.

The model's CEP location aligns with lattice-inspired results.

Abstract

I present the highlights of a recent study of the effective QCD phase diagram on the temperature T and quark chemical potential mu plane, where the strong interactions are modeled using the linear sigma model coupled to quarks. The phase transition line is found from the effective potential at finite T and mu taking into account the plasma screening effects. We find the location of the critical end point (CEP) to be (mu^CEP/T_c,T^CEP/T_c) \sim (1.2,0.8), where T_c is the (pseudo)critical temperature for the crossover phase transition at vanishing mu. This location lies within the region found by lattice inspired calculations. Since the linear sigma model does not exhibit confinement, I argue that the location is due to the proper treatment of the plasma screening effects and not to the size of the confining scale. I also comment on the extension of this study to determine the dependence of the CEP's location on the strength of an external magnetic field.