J/Psi Suppression in Pb-Pb Collisions: A Hint of Quark-Gluon Plasma   Production?
  The NA50 Collaboration has recently observed a strong suppression of J/Psi production in Pb-Pb collisions at 158 Gev/n. We show that this recent observation finds a quantitative explanation in a model which relates the suppression mechanism to the local energy density, whose value is higher in Pb-Pb collisions than in any other system studied previously. The sensitivity of the phenomenon to small changes in the energy density could be suggestive of quark-gluon plasma formation. 
Jean-Paul Blaizot, Jean-Yves Ollitrault