Two proton correlations from 158-A-GeV Pb + Pb central collisions

Abstract The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 A GeV has been measured by the NA49 experiment. The results are compared to model predictions from static thermal Gaussian proton source distributions and transport models rqmd and venus. An effective proton source size is determined by minimizing χ 2 /ndf between the correlation functions of the data and those calculated for the Gaussian sources, yielding σ eff =3.85±0.15(stat.) +0.60 −0.25 (syst.) fm. Both the rqmd and the venus model are consistent with the data within the error in the correlation peak region.