QCD phase diagram in chiral imbalance with self-consistent mean field approximation

TL;DR

This paper investigates how chiral imbalance affects the QCD phase diagram using a new self-consistent mean field approximation of the NJL model, revealing complex dependencies of the critical end point on chiral chemical potential and model parameters.

Contribution

It introduces a novel self-consistent mean field approach with a free parameter to study chiral imbalance effects on QCD phase structure, especially the critical end point.

Findings

Critical temperature initially increases then decreases with chiral chemical potential at high temperature.

Chiral chemical potential reduces the critical chemical potential at low temperature and high density.

The critical end point's temperature shows a non-monotonic dependence on chiral chemical potential.

Abstract

We employ a new self-consistent mean field approximation of NJL model, which introduces a free parameter $\alpha$ ($\alpha$ reflects the weight of different interaction channels), to study the effects of the chiral chemical potential $\mu_5$ on QCD phase structure, especially the location of the QCD critical end point (CEP). We find that, at a high temperature, the critical temperature of QCD phase transition smoothly increases with $\mu_5$ at the beginning, and then decreases rapidly. At low temperature and high baryon density region, the increase of the chiral chemical potential will reduce the critical chemical potential of phase transition. The temperature of the CEP shows a non-monotonic dependence on the chiral chemical potential with a long plateau around the maximum. At $\mu_5=0$, we found that the CEP will disappear when the $\alpha$ value is larger than 0.71 and will reappear when the $\mu_5$ increases. This study is important for exploring the QCD phase structure and the location of CEP in chiral imbalanced systems.