phi production in Pb-Pb collisions at 158 GeV/c per nucleon incident momentum

The production of vector mesons phi, rho and omega has been measured in Pb-Pb collisions at 158 GeV/c per nucleon incident momentum at the CERN/SPS. The muon spectrometer of experiment NA50 detects phi, rho and omega mesons via their mu(+)mu(-) decay channel in the collision center of mass rapidity range 0 less than or equal to gamma(CM) less than or equal to 1. The results reported here show that the relative production of the phi compared to the (rho + omega) and the phi multiplicity per participant nucleon (N-part) increase with the centrality of the collision. On the other hand, the (p + w) multiplicity per participant does not exhibit any N-part dependence within our errors. The inverse slope parameter as deduced from an exponential fit to the phi transverse mass distribution is 228 +/- 10 MeV. Our results are compared with those obtained by experiment NA49 and with theoretical calculations. (C) 2003 Elsevier Science B.V. All rights reserved.