Particle production in HRG with thermodynamically consistent EoS and partially deformable hadrons

TL;DR

This paper models particle yields in ultra-relativistic heavy-ion collisions using a thermodynamically consistent hadron resonance gas approach with excluded volume effects, revealing a double freeze-out scenario and successfully fitting experimental data across a wide energy range.

Contribution

It introduces a thermodynamically consistent HRG model with deformable hadrons and a double freeze-out scenario, improving the explanation of experimental particle yields.

Findings

The model fits experimental data from RHIC to LHC energies.

Evidence of separate freeze-out conditions for baryons and mesons.

Strangeness imbalance influences hadron yield ratios.

Abstract

In the present work, we analyze several strange as well as non-strange relative hadronic yields obtained in the ultra-relativistic heavy-ion collisions (URHIC) experiments over a wide range of center-of-mass collision energy ($\sqrt{s_{NN}}$). We invoke the formation of a hot and dense hadronic resonance gas (HRG) in the final stage following the URHIC. We use an earlier proposed thermodynamically consistent approach for obtaining the equation of state (EoS) of a HRG. It takes into account an important aspect of the hadronic interaction, viz., the hadronic hard-core repulsion, by assigning hard-core volumes to the hadrons, leading to an excluded volume (EV) type effect. We have invoked the bag model approach to assign hard-core volumes to baryons (antibaryons) while treating mesons to be point particles. We employ ansatz to obtain the dependence of the temperature (\textit{T}) and baryon chemical potential (BCP) of HRG system on the center-of-mass energy in URHIC. We also find strong evidence of a double freeze-out scenario, corresponding to baryons (antibaryons) and mesons, respectively. Strangeness (anti-strangeness) imbalance factor is also seen to play an important role in explaining the ratio of strange hadrons to the non-strange ones. The HRG model can explain the experimental data on various relative hadronic multiplicities quite satisfactorily over a wide range of $\sqrt{s_{NN}}$, ranging from the lowest RHIC energies to the highest LHC energies using one set of model parameters by obtaining the best theoretical fits to the experimental data using the minimum $\chi^{2}$/dof method.