The two-proton correlation function at midrapidity from Pb+Pb central collisions at 158 AGeV 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 CHI-square/ndf between the correlation functions of the data and those calculated for the Gaussian sources, yielding 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.
The two proton correlation function was analysed using proton from the rapidity range YRAP = 2.4 to 2.9 in the TOF analysis, and 2.9 to 3.4 in the dE/dx analysis. Momentum magnitude of the proton in the rest frame of the pair. All quoted errors are statistical only. (C=CORRECTED) relates to correlation function corrected for 44% contamination in the proton pair sample due to weak decay protons. (C=UNCORRECTED) means uncorrected correlation function.
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