CHARGED HADRON SPECTRA AND CORRELATIONS IN HEAVY ION COLLISIONS AT CERN: RESULTS FROM EXPERIMENT NA44

摘要

NA44 has measured single particle inclusive spectra and two-particle correla-tions of hadrons produced near midrapidity in a wide range of nuclear collisions from pBe to PbPb. Transverse mass distributions of pions, kaons, protons, antiprotons and deuterons are presented. A clear increase in the inverse slope parameters of these spectra is observed for the heavier particles as the size of the collision sys-tem increases, which may signal the existence of transverse flow. Two-pion and two-kaon correlations have been measured in both proton-nucleus and nucleus-nuc'eus collisions. High statistics data sets allow multidimensional fits of the two-particle correlation functions. The pion source parameters are large compared to the projectile radius, and larger than the kaon source pa-rameters from the same system. We observe a common 1/^/mr dependence for pions and kaons, indicating the presence of collective expansion. New results from the first Pb beam run at CERN are presented. Transverse mass distributions for pions, kaons and protons, and the proton yield at midrapidity are shown, along with two-pion correlations from PbPb collisions.