Baryon Number Transport in High Energy Nuclear Collisions

Abstract: Recent SPS data on the rapidity distribution of protons in p+S, p+Au and S+S collisions at 200 AGeV and preliminary Pb+Pb collisions at 160 AGeV are compared to HIJING and VENUS calculations as well as to predictions based on the Multi-Chain Model (MCM). The preliminary Pb data suggest that a linear dependence of the proton rapidity shift as a function of the nuclear thickness, as first observed in p+A reactions, may apply up to Pb+Pb reactions. The observed rapidity dependence of produced hyperons in both p+A and A+A reactions however cannot be explained in terms of such models without introducing additional non-linear effects.