J/ψ and ψ' nuclear absorption in p–A and S–U collisions at the CERN/SPS

We present preliminary NA50 results on J/$\psi$ and $\psi'$ production by 400 GeV/c incident protons on various targets. Production cross sections are determined for each p-target system. Their dependence on the target mass number A is studied using a Glauber model. The data obtained by experiment NA38 from S–U interactions at 200 GeV/nucleon incident momentum are also re-analysed which, together with our most recent 400 GeV and previous 450 GeV proton–nucleus results, lead to the J/$\psi$ absorption cross section in nuclear matter. We finally determine the expected 'normal' J/$\psi$ production in 158 GeV/nucleon Pb–Pb collisions as a function of centrality.