AZIMUTHAL CORRELATIONS AS A TEST FOR CENTRALITY IN HEAVY-ION COLLISIONS

Azimuthal correlations of particles emitted in collisions between Au-197 target nuclei and projectiles Ar-36 (at E/A = 35, 50, 80 and 110 MeV) and Xe-129 (at E/A = 50 MeV) have been measured with the MSU Miniball, a 4pi phoswich array with a low detection threshold. Various impact parameter filters, based on the charge-particle multiplicity, transverse energy and midrapidity charge are tested by their ability to suppress collective motion as measured by the azimuthal correlations. The usefulness of a directivity cut in selecting central collisions for these systems is evaluated.