Hadron resonance gas model with repulsive mean-field interactions: specific heat, isothermal compressibility and speed of sound

Abstract: We investigate the effect of repulsive interaction between hadrons on the specific heat ($C_V$), isothermal compressibility ($\kappa_{T}$) and the speed of sound ($C_s^2$) of hot and dense hadronic matter. The repulsive interactions are included through a mean-field approach where the single particle energy picks correction term due to mean field interactions between hadrons. This correction term is proportional to the number density of hadrons. We assume different mean-field interactions for mesons and baryons. We also confront $C_V$ and $C_s^2$ with existing lattice QCD simulation results. We find that the repulsive interactions have very strong effect on $C_V$ and $C_s^2$ while its effect on $\kappa_T$ is very mild. We finally discuss the implications of our results in the context of heavy-ion collision experiments.