$\frac{J}{\psi }$ Suppression in Pb-Pb Collisions: A Hint of Quark-Gluon Plasma Production?

The NA50 Collaboration has recently observed a strong suppression of $\frac{J}{\psi }$ production in Pb-Pb collisions at 158 GeV/nucleon. 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.