J PSI AND PSI' SUPPRESSION IN HIGH-ENERGY HEAVY-ION COLLISIONS/

The anomalous suppression of J/psi production in Pb-Pb collisions at 1 58A GeV observed by the NA50 Collaboration can be explained as due to the occurrence of a new phase of strong J/psi absorption, which sets i n when the local energy density exceeds about 3.4 GeV/fm(3). The pecul iar behavior of the psi/psi ratio in p-A and nucleus-nucleus collision s can be understood as due to approximately equal psi-N and psi'-N abs orption cross sections, but greater absorption cross sections for psi' than J/psi with regard to absorption by soft particles and matter in the new phase.