THE SUPPRESSION OF THE J / PSI IN HIGH-ENERGY NUCLEUS NUCLEUS COLLISIONS: EXPERIMENTAL DATA AND MODELS

The main results on the J/<1> suppression observed in the NA38 experiment in oxygen-uranium, oxygen-copper and sulphur-uranium central collisions at 200 GeV/nucleon are summarized. An analysis is made of the models which have been proposed to try explaining the experimental data. Two classes of models are considered: one which assumes the existence of a quark-gluon plasma, another which assumes J/ absorption by inelastic scattering in some hot dense hadronic matter, either without or with initial state parton interactions. The present status of the subject is summarized in the conclusions.