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

Results are presented on rho + omega, phi and J/psi production in p-W and (32)S-W interactions at 200 GeV/c/nucleon measured via the dimuon decay in a large kinematic region. The data are normalized to the charged particle multiplicity in the same rapidity interval. They have been collected using the HELIOS/3 muon spectrometer at the CERN SPS. The ratio B sigma(phi)(B sigma(rho) + B sigma(omega)), where B is the relevant resonance mu mu 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 phi's per charged particle. The ratio is measured in different intervals of p tau and rapidity. It is not clearly dependent on pr, but is larger at higher rapidities. J/psi production, likewise normalized to charged multiplicity, is significantly lower in S-W compared to p-W interactions.