Charmonium suppression in heavy-ion collisions

Data and their interpretations are reviewed for J/psi and psi' production i n heavy-ion collisions with particular emphasis on the recently reported an omaly in Pb-Pb reactions. The observed suppressions in pA collisions are di scussed in terms of final-state absorption of a pre-meson and the p(T) dist ributions due to parton scattering in the initial state. The experimental s etup is described and the various results for J/psi and psi' suppressions, including their p(T)-dependence, are presented. The data, in particular the observed anomalous suppression in Pb-Pb collisions, are discussed in the l ight of the proposed ideas, among them quark-gluon plasma formation: and su ppression via co-movers.