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

Abstract

Results are presented on + !, and J = 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 i n terval. They have been collected using the HELIOS/3 muon spectrometer at the CERN SPS. The ratio =(+ !) increases between proton and sulphur projectiles, and is further enhanced going from peripheral to central nucleus-nucleus interactions. This results from an increase in the number of produced 's per charged particle. The increase in the ratio =(+ !) is not clearly dependent on p T , but appears larger at higher rapidities, due to kinematic eects in conjunction with varying acceptance. J = production, likewise normalized to charged multiplicity, i s signicantly lower in S{W compared to p{W interactions.