Universal descriptions of chemical freeze-out based on pressure and specific heat

Abstract

The lattice QCD data of pressure and the energy density have been used to extract the hadronic radius parameter of the excluded volume hadron resonance gas (EVHRG) model. The equation of state can be described well with the extracted radius parameter [Formula: see text] fm. Specific heat is also calculated in the EVHRG model. Further, two new universal descriptions of chemical freeze-out parameters have been introduced based on pressure and specific heat, respectively. It is shown that the chemical freeze-out parameters obtained at various [Formula: see text] in ideal hadron resonance gas (HRG) model approximately correspond to [Formula: see text] and [Formula: see text], respectively. These two quantities are important to describe the thermodynamic properties of the hadronic matter created in heavy-ion collision experiment. The sensitivity of universal chemical freeze-out lines on repulsive interaction is also studied. It has been observed that the behaviors of chemical freeze-out lines for [Formula: see text] and [Formula: see text] in EVHRG model remain similar to ideal HRG model for the best fit value of hadronic radii.