Proton–proton, anti-proton–anti-proton, proton–anti-proton correlations in Au?+?Au collisions measured by STAR at RHIC

摘要

The analysis of two-particle correlations provides a powerful tool to study the properties of hot and dense matter created in heavy-ion collisions at ultra-relativistic energies. Applied to identical and non-identical hadron pairs, it makes the study of space-time evolution of the source in femtoscopic scale possible. Baryon femtoscopy allows extraction of the radii of produced sources which can be compared to those deduced from identical pion studies, providing complete information about the source characteristics. In this paper we present the correlation functions obtained for identical and non-identical baryon pairs of protons and anti-protons. The data were collected recently in Au+Au collisions at (sqrt{s_{NN}})?=62?GeV and (sqrt{s_{NN}})?=200?GeV by the STAR detector at the RHIC accelerator. We introduce corrections to the baryon–baryon correlations taking into account: residual correlations from weak decays, particle identification probability and the fraction of primary baryons. Finally we compare our results to theoretical predictions.