Hadron Correlations and Fluctuations in 40, 80, and 158 AGeV/c Pb-Au Collisions

Abstract

Measurements of HBT correlations and event-by-event fluctuations of mean pT and the net charge in Pb-Au collisions at 40, 80, and 158 AGeV/c are presented. From comparisons of HBT radii measured from AGS to RHIC energies, a universal mean free path of pions at the thermal freeze-out of about 1 fm is derived. Non-statistical mean pT fluctuations of about 0.7 % are measured, which are somewhat smaller than fluctuations at RHIC. No indication for the QCD critical point is observed. Fluctuations of the net charge are reproduced by RQMD and URQMD models, but significantly larger than prediction in equilibrated QGP.