Phase Structure of QCD Matter in a Chiral Effective Model with Quarks

TL;DR

This paper investigates the phase structure of QCD matter using a unified hadron-quark effective model, revealing a smooth crossover transition consistent with lattice QCD and thermal models, and discusses the challenges of detecting a critical end-point in heavy-ion collisions.

Contribution

It introduces a comprehensive hadron-quark effective model that captures the QCD phase transition and its dependence on temperature and chemical potential, aligning with recent lattice and experimental data.

Findings

Smooth crossover transition at low chemical potential

Transition temperature and curvature match lattice QCD estimates

Potential critical end-point at high chemical potential and low temperature

Abstract

Using a unified hadron-quark effective model for the QCD equation of state, this paper studies the phase structure of strongly interacting matter in a wide range of temperature and baryonchemical potential. At small potentials the model yields a smooth cross-over to chirally restored matter with a transition temperature and curvature in line with recent lattice QCD estimates and thermal model fits of freeze-out curves. Trajectories of constant entropy per net baryon number show a clear dependence on the particle composition in the model and on repulsive vector field interactions. Although the model might feature a critical end-point at a rather high baryonchemical potential and low temperature, probing it in heavy-ion collisions might be highly challenging due to a large thermodynamic spread of matter in the collision fireball.