RHIC p ⊥ - Spectra in a Single - Freeze - Out Model ∗

In this talk we present a simple model describing the p⊥-spectra of various hadrons measured recently at RHIC. Our approach combines the thermal model, used frequently in the studies of the relative hadron yields [1-10], with a model of the hydrodynamic expansion of matter at freeze-out. The main assumptions of the model are as follows [11-13]: First of all, we assume that the chemical freeze-out and the thermal freeze-out occur at the same time. This means that we neglect elastic rescattering after the chemical freeze-out. Secondly, we include all hadronic resonances in both the calculation of the hadron multiplicities and the spectra. In particular, all cascade decays are taken into account exactly in a semi-analytic fashion. Finally, we assume a simple form of the freeze-out hypersurface, which is a generalization of the Bjorken model [14] (see also [15-20])