Survey of Recent Results from the PHOBOS Experiment at RHIC

Abstract

We present an overview of the latest results for interactions of Au+Au ions at center‐of‐mass energies of SNN of 56, 130 and 200 GeV obtained by the PHOBOS collaboration at the Relativistic Heavy Ion Collider (RHIC). These data have allowed us to perform an extensive study of the pseudorapidity density of primary charged particles as a function of incident energy, centrality and pseudorapidity. Our results show a non‐trivial evolution of particle densities with both centrality and collision energy, reaching significantly higher values per participating nucleon than at lower energies or in nucleon‐nucleon collisions. Further we present results on the azimuthal asymmetry of particle production observed in the SNN of 130 GeV data set. The observed strong event anisotropy of v2max > 0.06, reaching beyond the value predicted in hadronic cascade models, indicates a closer approach to local thermal equilibration than at lower collision energies. The measured antiparticle‐particle ratios of production rates for pions kaons and protons in central Au+Au interactions at SNN of 130 GeV are compatible with predictions from statistical models, showing an approach to a baryon free region in mid‐rapidity with the increase in collision energy.