Charmonia states suppression and transverse momentum distribution in Pb-Pb collisions at the CERN SPS

We present the results of experiment NA50 on the production of charmonia states in Pb-Pb collisions at 158 GeV/c per nucleon. For the most peripheral collisions the experimental data agree with ordinary nuclear absorption as deduced from proton and light nuclei induced collisions. For central collisions, we observe an anomalous suppression which significantly departs from normal nuclear absorption and which could result from Debye color screening in a deconfined quark-gluon phase. The dependence of the transverse momentum distributions on the centrality of the Pb-Pb collision is also investigated.