Study of vector mesons in dimuon production in a large kinematic region in p-W and S-W interactions at 200 GeV/c/nucleon

Results are presented on p + ω,o and J/ψ production in p-W and 32S-W interactions at 200GeV/c/nucleon measured via the dimuon decay in a large kinematic region. The data are normalized to the charged particlemultiplicity in the same rapidity interval. They have been collected using the HELIOS/3 muon spectrometer at the CERN SPS. The ratio Bσo/ (Bσρ + Bσω), where B is the relevant resonance µµ branching fraction, increases between proton and sulphur projectiles, and is somewhat enhanced going from peripheral to central S-W interactions. This results from an increase in the number of produced o’s per charged particle. The ratio is measured in different intervals of pt and rapidity. It is not clearly dependent on pt, but is larger at higher rapidities. J/Ψ production, likewise normalized to charged multiplicity, is significantly lower in S-W compared to p-W interactions.