Muon pair and vector meson cross-sections in p-W and SU collisions at 200 GeV/nucleon

Muon pair production is studied in p-W and SU collisions at 200 GeV per nucleon, as a function of transverse momentum PTμμ. The inclusive ϱ+ω and Φ differential cross-sections dσ dP T are measured in the dimuon decay channel, for PT ≥ 0.6 GeV/c, in the central rapidity region, 3.0≤ y ≤ 4.0. Assuming the power law A-dependence σ = σ0(Abeam·Atarget)α, the study of the integrated cross-sections for p-W and SU collisions leads to αϱ+ω = 1.00±0.02±0.07 and αΦ = 1.23±0.03±0.05, showing clear evidence of Φ enhancement in SU interactions as compared to p-W collisions.