Production of ϱ + ω and Φ in p-W and SU collisions at 200 GeV/nucleon

The transverse mass differential cross-sections for the ϱ + ω and Φ resonances is obtained, in the central rapidity region, in p - W and S  U interactions at 200 GeV/nucleon. The measured ϱ + ω and Φ temperatures are ∼ 15% higher in S  U as compared to p - W collisions. The ratio of cross-sections times branching ratios into the dimuon channel B Φ σ Φ (B ϱ σ ϱ + B ω σ ω ) is studied as a function of the energy density reached in the collision and of the dimuon transverse momentum. The measured ratio is 2 to 3 times larger in S  U than in p - W collisions and an enhancement is observed in S  U interactions with increasing energy density.