Transverse energy fluctuations and the pattern of J/psi suppression in Pb-Pb collisions.

The NA50 Collaboration has recently observed that the J/psi production rate in Pb-Pb collisions decreases more rapidly as a function of the transverse energy for the most central collisions than for less central ones. We show that this phenomenon can be understood as an effect of transverse energy fluctuations in central collisions. A good fit of the data is obtained using a model which relates J/psi suppression to the local energy density. Our results suggest that the J/psi is completely suppressed at the highest densities achieved in Pb-Pb collisions.