Enhanced antiproton production in Pb(160 AGeV)+Pb reactions: evidence for quark gluon matter?
arXiv:hep-ph/0004045 · doi:10.1016/S0370-2693(00)00643-2
Abstract
The centrality dependence of the antiproton per participant ratio is studied in Pb(160 AGeV)+Pb reactions. Antiproton production in collisions of heavy nuclei at the CERN/SPS seems considerably enhanced as compared to conventional hadronic physics, given by the antiproton production rates in $pp$ and antiproton annihilation in $\bar{p}p$ reactions. This enhancement is consistent with the observation of strong in-medium effects in other hadronic observables and may be an indication of partial restoration of chiral symmetry.