Strangeness production in heavy ion collisions at SPS and RHIC within two-source statistical model

Abstract

The experimental data on hadron yields and ratios in central Pb+Pb and Au+Au collisions at SPS and RHIC energies, respectively, are analysed within a two-source statistical model of an ideal hadron gas. These two sources represent the expanding system of colliding heavy ions, where the hot central fireball is embedded in a larger but cooler fireball. The volume of the central source increases with rising bombarding energy. Results of the two-source model fit to RHIC experimental data at midrapidity coincide with the results of the onesource thermal model fit, indicating the formation of an extended fireball, which is three times larger than the corresponding core at SPS.