On Locating the Critical End Point in QCD Phase Diagram

TL;DR

This paper models the QCD phase diagram using quasiparticle models and lattice data, identifying a critical end point where a first-order phase transition transitions to a crossover.

Contribution

It introduces a new equation of state for baryons and mesons with repulsive interactions and locates the critical end point in the QCD phase diagram.

Findings

Good agreement between models and lattice QCD data.

Identification of the critical end point in the phase diagram.

Development of a new EOS incorporating baryon interactions.

Abstract

We use the available two different self-consistent formulations of quasiparticle models and extend their applications for the description of quark gluon plasma (QGP) at non-vanishing baryon chemical potentials. The thermodynamical quantities calculated from these models are compared with the values obtained from lattice simulations and a good agreement between theoretical calculations and lattice QCD data suggests that the values of the parameters used in the paper are consistent. A new equation of state (EOS) for a gas of extended baryons and pointlike mesons is presented here which incorporates the repulsive hard-core interactions arising due to geometrical size of baryons. A first order deconfining phase transition is constructed using Gibb's equilibrium criteria between the hadron gas EOS and quasiparticle model EOS for the weakly interacting quark matter. This leads to an interesting finding that the phase transition line ends at a critical end point beyond which a crossover region exists in the phase diagram.