Energy dependence of hyperon production in central Pb+Pb collisions at the CERN-SPS

Abstract

Recent results on hyperon production in central Pb+Pb collisions at 20, 30, 40, 80 and 158 A GeV obtained by the NA49 experiment at the CERN-SPS are presented and compared to the results at lower (AGS) and higher (RHIC) energies. New measurements of Λ at 20 A GeV and at 30 A GeV are shown for the first time. The particle ratios are compared to the predictions of models which do not assume a deconfinement phase transition such as the hadron gas model and string hadronic models. Finally, their relation to the onset of deconfinement at low SPS energies is discussed.