Impact of the vector interaction on the phase structure of QCD matter

TL;DR

This paper explores how including a vector interaction and entanglement effects in a Polyakov-loop extended model of QCD influences the phase diagram, especially the critical end-point, aligning better with lattice data.

Contribution

It introduces a Polyakov-loop dependent vector interaction and entanglement effects into the model, providing new insights into the QCD phase structure and critical point location.

Findings

Finite vector interaction strength G_v improves model agreement with lattice data.

Non-zero G_v and entanglement affect thermodynamic observables and crossover boundary curvature.

The model better predicts the phase diagram features of QCD matter.

Abstract

The 2-flavor Polyakov-loop extended model is generalized by taking into account the effective four-quark vector-type interaction with the coupling strengths, which are endowed with a dependence on the Polyakov field $\Phi$. The effective vertex generates entanglement interaction between the Polyakov loop and the chiral condensate. We investigate the influence of an additional quark vector interaction and the entanglement interaction on the location of the critical end-point at the given chemical potential or quark density. It is shown that the finite value of the vector interaction strength $G_{\rm v}$ improves the model agreement with the lattice data. The influence of the non-zero $G_{\rm v}$ and entanglement on the thermodynamic observables and the curvature of the crossover boundary in the $T-\mu$ plane is also examined.