Freeze-out dynamics at RHIC

Abstract

Investigation of the final hadronic state properties of ultra-relativistics pp and Au+Au collisions supplies information on freeze-out conditions at RHIC and possible insights into early stages of these collisions. A variety of particle spectra measured by STAR are studied within the framework of chemical and local kinetic equlibrium models. Here we present the extracted chemical and final kinetic freeze-out temperatures, strangeness saturation factor, final collective flow velocity, and the inferred flow velocity at chemical freeze-out. In light of those measurements we disscuss dynamical evoution of the collission system.