Phi Meson Production In Gold-Gold Collisions at the Relativistic Heavy Ion Collider

Results from the first measurement of mid-rapidity &phis; vector meson production in <italic>Au</italic> + <italic>Au</italic> collisions at RHIC (<math> <f> <rad><rcd>s<inf>NN</inf></rcd></rad></f> </math> = 130 GeV) are described. Using the STAR detector, &phis; mesons were measured from the &phis; &rarr; <italic>K</italic><super>+</super><italic> K</italic><super>&minus;</super> decay channel. For the 11% most central collisions, the slope parameter from an exponential fit to the transverse mass distribution is <italic>T</italic> = 379 &plusmn; 51 (stat) &plusmn; 45 (syst) MeV, the yield <italic>dN/dy</italic> = 5.73 &plusmn; 0.37 (stat) &plusmn; 0.57 (syst) per event and the ratios <italic>N</italic>_&phis;/<italic>N</italic>_{h<super>&minus;</super>} and <italic>N</italic>_&phis;/<italic> N</italic>_{K<super>&minus;</super>} are found to be 0.021 &plusmn; 0.001 (stat) &plusmn; 0.004 (syst) and 0.14 &plusmn; 0.01 (stat) &plusmn; 0.03 (syst). Within the statistics available, the mid-rapidity ratios, <italic> N</italic>_&phis;/<italic>N</italic>_{h<super>&minus;</super>} and <italic>N</italic>_&phis;/<italic>N</italic>_{K<super>&minus; </super>}, and the slope parameter for the &phis; meson do not change for the selected centrality bins. The slope parameter increases in heavy ion collisions as a function of <math> <f> <rad><rcd>s<inf>NN</inf></rcd></rad></f> </math> from the BNL AGS to CERN SPS to RHIC. Comparisons of the &phis; meson slope parameter to the slope parameters for the &pi;, <italic>K</italic>, and <italic>p&macr;</italic> measured at STAR indicate that the &phis; meson deviates from a systematic trend of a mass dependence of the slope parameter, suggesting that the &phis; meson may not interact as strongly as anti-protons during a collective expansion of the collision system. The production of &phis; mesons relative to negatively charged hadrons (<italic>N</italic>_&phis;/<italic>N</italic>_{h<super>&minus;</super>}) in nucleus-nucleus collisions indicates an overall increase in strange and anti-strange quark production from <math> <f> <rad><rcd>s<inf>NN</inf></rcd></rad></f> </math> = 4.9 GeV to <math> <f> <rad><rcd>s<inf>NN</inf></rcd></rad></f> </math> = 130 GeV. When comparing the <italic>N</italic>_&phis;/<italic> N</italic>_{K<super>&minus;</super>} ratio in <italic>p</italic> + <italic> p</italic>, <italic>p</italic> + <italic>p&macr;</italic>, <italic>Pb</italic> + <italic>Pb</italic> and <italic>Au</italic> + <italic>Au</italic> collisions, we find that the ratio is independent of both system size and energy from the AGS to the Tevatron. This result suggests some universal relationship between the mechanisms responsible for &phis; and <italic>K</italic><super> &minus;</super> meson production.