(Cont.) In the mid-rapidity region, the yield of charged particles evolves smoothly as a function of [the square root of] sNN and collision centrality. We compare our results with a compilation of data from lower energy p + p, p + A and A + A collisions and discuss their implications for various phenomenological models of particle production.

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at (square root)(s{sub NN}) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and ee− data. Nch/N{sub part}/2 in nuclear collisions at high energy scales with (square root)s in a similar way as N{sub ch} in ee− collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

Transverse energy (E{sub T}) distributions have been measured for Au+Au collisions at (square root)s{sub NN} = 200 GeV by the STAR collaboration at RHIC. E{sub T} is constructed from its hadronic and electromagnetic components, which have been measured separately. E{sub T} production for the most central collisions is well described by several theoretical models whose common feature is large energy density achieved early in the fireball evolution. The magnitude and centrality dependence of E{sub T} per charged particle agrees well with measurements at lower collision energy, indicating that the growth in E{sub T} for larger collision energy results from the growth in particle production. The electromagnetic fraction of the total E{sub T} is consistent with a final state dominated by mesons and independent of centrality.

The PHOBOS experiment at RHIC has measured the multiplicity of primary charged particles as a function of centrality and pseudorapidity in Au+Au collisions at (square root)(s{sub NN}) = 19.6, 130 and 200 GeV. Two observations indicate universal behavior of charged particle production in heavy ion collisions. The first is that forward particle production, over a range of energies, follows a universal limiting curve with a non-trivial centrality dependence. The second arises from comparisons with pp/{bar p}p and ee− data. N{sub ch}/N{sub part}/2 in nuclear collisions at high energy scales with (square root)s in a similar way as N{sub ch} in ee− collisions and has a very weak centrality dependence. These features may be related to a reduction in the leading particle effect due to the multiple collisions suffered per participant in heavy ion collisions.

This thesis reports the measurement of the inclusive charged particle (h[sup+]+ h[sup -]) p[perpendicular] spectra for 1.7

This thesis presents the first J/psi production analysis of Au+Au reactions at forward rapidity at [square root]sNN = 200 GeV. In the second year of RHIC running, design energy was achieved in the collisions of both Au+Au ions and proton+proton reactions. The production of the J/psi is measured by the PHENIX experiment in Au+Au collisions as well as in proton-proton collisions. The scientific goal is to investigate the nature of hot, dense nuclear matter capitalizing on the unique properties of the J/psi as a probe of this matter. Recent experimental results by the NA50 collaboration at CERN strongly deviate from the conventional picture that successfully describes data at lower energies. The importance of such a measurement is demonstrated by the wide spectrum of theoretical explanations concerning the existing data. The merits of these models will be explored in a systematic and comprehensive study of the J/psi and open charm in collisions of a variety of species and energy. A survey of the theoretical models is presented and the relevant open charm and J/psi PHENIX measurements are compared.