Anomalous J/ψ production in Pb-Pb collisions at 158 GeV/nucleon

J/ψ suppression in Pb-Pb collisions at CERN has been measured by the NA50 experiment in 1996 with a much improved statistics allowing a detailed centrality dependence study. While the peripheral collisions seem to agree with the results previously obtained with light projectiles, the more central collisions show a much stronger suppression. These results are still preliminary but this discontinuity should rule out the interpretation of J/ψ suppression in terms of destructive interactions with comoving particles. (authors)