Results from the PHOBOS experiment at RHIC

Au+Au collisions have been studied at center-of-mass energies of \(\sqrt {s_{NN} } = 56\) and 130 GeV using the PHOBOS detector at RHIC. Charged particle multiplicites have been measured as a function of center-of-mass energy, centrality and pseudo-rapidity, η. A total of 4100±400 charged particles are observed in the pseudo-rapidity range −5.4 < η < 5.4 for the most central collisions. A strong elliptic flow signal is seen in peripheral collisions at η = 0. The measurement of an antiprotons to protons ratio of \(\bar p/p = 0.60 \pm 0.04(stat) \pm 0.06(syst)\) indicates that a nearly baryon-free region is created at midrapidity.