Charged Hadron Spectra in Au+Au Collisions at a Centre-of-Mass Energy of 130 GeV

Abstract

This work concentrates on measurement of global hadronic observables in Au+Au interactions at a centre-of-mass energy per nucleon pair of 130 GeV, which mainly address conditions in the final state of the collision. The minimum bias multiplicity distribution, the transverse momentum (pT), and pseudorapidity (eta) distributions for charged hadrons (h-, h+) are presented. Results on identified pi- transverse mass (mT) and rapidity (y) distributions are also discussed. The data were taken with the STAR detector at BNL-RHIC with emphasis on particles near mid-rapidity. We find that the h- multiplicity at mid-rapidity for the 5% most central interactions is dN/d eta = 280 +/- 1 +/- 20, an increase per participant of 38% relative to p-pbar collisions at similar energy. The mean transverse momentum is 0.508 +/- 0.012 GeV/c and is larger than in Pb+Pb collisions at lower energies. The scaling of the h- yield per participant nucleon pair, obtained via a ratio of Au+Au to p-pbar pT distributions, is a strong function of pT. The pseudorapidity distribution is almost constant within |eta|<1. The pi- rapidity distribution is also flat around mid-rapidity in the region y<0.8, with a yield of pions for central collisions of dN/dy = 287 +/- 1 +/- 21. However, the slope of the mT distributions is not the same for different rapidity bins, suggesting that boost-invariance is not fully achieved in the collisions.