Particle Ratios in a Multi Component Non-Ideal Hadron Resonance Gas

Abstract

We have considered formation of a multi component non-ideal hot and dense gas of hadronic resonances in the ultra-relativistic heavy-ion collisions. In the statistical thermal model approach the equation of state (EoS) of the non interacting ideal hadron resonance gas (IHRG) does not incorporate either the attractive part or the short range repulsive part of the baryonic interaction. On the other hand in the non-ideal hadron resonance gas (NIHRG) model we can incorporate these interactions using the Van der Waals (VDW) type approach. Studies have been made to see its effect on the critical parameters of the quark-hadron phase transition. However, it can also lead to modifications in the calculated relative particle yields. In this paper we have attempted to understand the effect of such Van der Waals type interactions on the relative particle yields and also studied their dependences on the system thermal parameters, such as the temperature and baryon chemical potential ({\mu}_B). We have also taken into account the decay contributions of the heavier resonances. These results on particle ratios are compared with the corresponding results obtained from the point-like i.e. non interacting IHRG model. It is found that the particle ratios get modified by incorporating the Van der Waals type interactions, especially in a baryon rich system which is expected to be formed at lower RHIC energies, SPS energies and in the forthcoming CBM experiments due to high degree of nuclear stopping in these experiments.