Chemical Equilibration and the Hadron-QGP Phase Transition

Abstract

We discuss recent experimental results on hadron multiplicities in ultra-relativistic nuclear collisions. The data for central collisions are in quantitative agreement with predictions of a thermal model assuming full chemical equilibration. It is argued that this provides strong, albeit indirect, evidence for the formation of a partonic phase in the collision prior to hadron production.

Comments: Contribution to CRIS2000 conference, to be published in Nucl. Phys. A