QCD Phase Boundary and Critical Point in a Bag Model Calculation

TL;DR

This paper presents a new equation of state for QCD matter, identifying a phase boundary and critical point consistent with lattice gauge predictions, using a bag model approach with extended baryons and mesons.

Contribution

It introduces a novel EOS incorporating baryon size effects and maps the QCD phase boundary with a critical point using a bag model framework.

Findings

Identifies a first order deconfining phase transition line.

Locates a critical point where the transition becomes crossover.

Reproduces the shape of the lattice gauge phase boundary.

Abstract

Location of critical point and mapping the QCD phase boundary still exists as one of the most interesting and studied problems of heavy-ion physics. A new equation of state (EOS) for a gas of extended baryons and pointlike mesons is presented here which accounts for the repulsive hard-core interactions arising due to the geometrical size of the baryons. A first order deconfining phase transition is obtained using Gibbs' equilibrium criteria and a bag model EOS for the weakly interacting quark matter. It is interesting to find that the phase transition line ends at a critical point beyond which a cross-over region exists between hot-dense meson gas and quark-antiquark gluon matter. Our curve resembles in shape closely with the predictions of the available lattice gauge calculations and also reproduces the conjectured phase boundary.