Abstract

We report on the rapidity and centrality dependence of proton and antiproton transverse mass distributions from Au-197+Au-197 collisions at roots(NN)=130 GeV as measured by the STAR experiment at the Relativistic Heavy Ion Collider (RHIC). Our results are from the rapidity and transverse momentum range of parallel toyparallel to0.5 and 0.35(t)1.00 GeV/c. For both protons and antiprotons, transverse mass distributions become more convex from peripheral to central collisions demonstrating characteristics of collective expansion. The measured rapidity distributions and the mean transverse momenta versus rapidity are flat within \y\0.5. Comparisons of our data with results from model calculations indicate that in order to obtain a consistent picture of the proton (antiproton) yields and transverse mass distributions the possibility of prehadronic collective expansion may have to be taken into account.