Charged particle multiplicity and transverse energy in Au - Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV

Abstract

This paper presents the results for the charged-particle multiplicity and transverse energy distributions at mid-rapidity in Au - Au collisions at $\sqrt{s_{_{NN}}}=130$ GeV measured with the PHENIX detector at RHIC. The values of $dN_{ch}/d\eta_{|\eta=0}$ and $dE_{T}/d\eta_{|\eta=0}$, analyzed as a function of centrality, show a consistent steady rise. For the 5% most central collisions they are $\sim70$% larger compared to the SPS results for Pb-Pb collisions at $\sqrt{s_{_{NN}}}=17.2$ GeV. The ratio of $<E_{T}>/<N_{ch}>$ remains constant as a function of centrality at 0.8 GeV, as also observed at the SPS at CERN and at the AGS at BNL.