Abstract

We report the STAR measurement of phi meson production in Au + Au and p + p collisions at root s(NN) = 200 GeV. Using the event mixing technique, the phi spectra and yields are obtained at mid-rapidity for five centrality bins in Au + Au collisions and for non-singly-diffractive p + p collisions. It is found that the phi transverse momentum distributions from Au + An collisions are better fitted with a single-exponential while the p + p spectrum is better described by a double-exponential distribution. The measured nuclear modification factors indicate that phi production in central An + An collisions is suppressed relative to peripheral collisions when scaled by the number of binary collisions ( N-bin>). The systematics of p(t)> versus centrality and the constant phi/K- ratio versus beam species, centrality, and collision energy rule out kaon coalescence as the dominant mechanism for phi production. (c) 2005 Elsevier B.V. All rights reserved.