Hadron resonance gas EoS and the fluidity of matter produced in HIC

TL;DR

This paper enhances the hadron resonance gas model by including excluded volume effects and Hagedorn states, successfully matching lattice QCD results and estimating the matter's fluidity in heavy-ion collisions.

Contribution

It introduces a modified HRG model with excluded volume corrections and Hagedorn states, aligning well with lattice QCD data at finite chemical potential.

Findings

The modified HRG model reproduces lattice QCD results up to T=160 MeV.

The model estimates shear viscosity relevant for heavy-ion collisions.

Incorporation of Hagedorn states improves the EoS accuracy.

Abstract

We study the equation of state (EoS) of the hot and dense hadron gas by incorporating the excluded volume corrections into the ideal hadron resonance gas model (HRG). The total hadron mass spectrum of the model is the sum of discrete mass spectrum consisting all the experimentally known hadrons and the exponentially rising continuous Hagedorn states. We confront the EoS of the model with lattice quantum chromodynamics (LQCD) results at finite baryon chemical potential. We find that this modified HRG model reproduce the LQCD results up to T = 160 MeV at zero as well as finite baryon chemical potential. We further estimate the shear viscosity coefficient within ambit of this model in the context of heavy-ion collision experiments.