Latest documents http://publikationen.ub.uni-frankfurt.de/index/index/ Mon, 26 Sep 2005 09:12:26 +0200 Mon, 26 Sep 2005 09:12:26 +0200 http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3870 A non-monotonic energy dependence of the K + / pi + ratio with a sharp maximum close to 30 A GeV is observed in central Pb+Pb collisions. Within a statistical model of the early stage, this is interpreted as a sign of the phase transition to a QGP, which causes a sharp change in the energy dependence of the strangeness to entropy ratio. This observation naturally motivates us to study the production of multistrange hyperons (Xi, Omega) as a function of the beam energy. Furthermore it was suggested that the kinematic freeze-out of Omega takes place directly at QGP hadronization. If this is indeed the case, the transverse momentum spectra of the Omega directly reflect the transverse expansion velocity of a hadronizing QGP. In this report we show preliminary NA49 results on Omega - and Omega + production in central Pb+Pb collisions at 40 and 158 A GeV and compare them to measurements of Xi - and Xi + production in central Pb+Pb collisions at 30, 40, 80 and 158 A GeV. Michael Kosta Mitrovski; NA49 Collaboration preprint http://publikationen.ub.uni-frankfurt.de/frontdoor/index/index/docId/3870 Mon, 26 Sep 2005 09:12:26 +0200