Study of freeze-out dynamics in STAR at RHIC Beam Energy Scan Program

Abstract

The STAR detector at RHIC, due to its large uniform acceptance and excellent particle identification capabilities, has measured a variety of hadron species (π±, K±, p, , K0s, Λ, , Ξ-, ) produced in Au+Au collisions at 7.7, 11.5, 27 and 39 GeV. These data are part of the Beam Energy Scan (BES) program at RHIC and provide an opportunity to measure the yields and transverse momentum spectra (pT) of the particles produced in the collisions. The corresponding measurements allow to study the freeze-out properties and dynamics of heavy ion collisions. A statistical thermal model analysis of particle production in BES energies in both grand canonical and strangeness canonical ensembles, is used to extract the chemical freeze-out parameters. The pT spectra, particle ratios, and the energy and centrality dependence of freeze-out parameters determined from the thermal fit of particle ratios are discussed.