Results on 40 A GeV/c PbPb collisions from the NA57 experiment

Abstract The NA57 experiment has been designed to study the onset of the strange baryon and antibaryon enhancements in Pb Pb with respect to p-Be collisions, first observed by WA97 at 160 A GeV/ c . NA57 has extended the WA97 measurements to investigate the evolution of strangeness enhancement over a wider centrality range and as a function of the beam energy. Results on hyperon production in central Pb Pb collisions at 40 A GeV/ c are presented and compared with those obtained at higher energy, in the same centrality range.