  We present a new calculation of the pi-J/psi dissociation cross sections
within the Constituent Quark-Meson Model recently introduced. To discuss the
absorption of J/psi in heavy-ion collisions, we assume the J/psi to be produced
inside a thermalized pion gas, as discussed by Bjorken, and introduce the
corrections due to absorption by nuclear matter as well. We fit the absorption
length of the J/psi to the data obtained at the CERN SPS by the NA50
Collaboration for Pb-Pb collisions. Collisions of lower centrality allow us to
determine the temperature and the energy density of the pion gas. For both
these quantities we find values close to those indicated by lattice gauge
calculations for the transition to a quark-gluon plasma. A simple extrapolation
to more central collisions, which takes into account the increase of the energy
deposited due to the increased nucleon flux, fails to reproduce the break in
J/psi absorption indicated by NA50, thus lending support to the idea that an
unconfined quark-gluon phase may have been produced. This conclusion could be
sharpened by analysing in a similar way, as a function of centrality, other
observables such as strange particle production.
