Systematic of Particle Thermal Freeze-out in a Hadronic Fireball at RHIC

Abstract

We attempt to describe the rapidity and transverse momentum spectra of strange as well as non-strange hadrons e.g. cascade,cascadebar, lambda , lambdabar, proton, protonbar,(omega+omegabar, Kaon, anti-Kaon and their ratios in the ultra-relativistic collisions of gold nuclei at (Root sNN)=200 GeV. This is done by using a statistical thermal freeze-out model which incorporates the rapidity (collision) axis as well as transverse direction boosts developed within an expanding hot and dense hadronic fluid (fireball) till the final freeze-out. We determine the thermo-chemical freeze-out conditions particularly in terms of the temperature, baryon chemical potential and collective flow effect parameters for different particle species. The parameters indicate occurrence of freeze-out of the singly and doubly strange hyperon species at somewhat earlier times during the evolution of the fireball. The experimental data of the transverse momentum and rapidity distribution are well reproduced. The contribution of heavier hadronic resonance decay is taken into account.