Results on Lambda and Xi production in Pb-Pb collisions at 160 GeV/c per   nucleon from the NA57 experiment
  The NA57 experiment has been designed to study the onset of enhanced production of strange baryons and anti-baryons in Pb-Pb collisions with respect to p-Be collisions. This enhancement is considered a sensitive signature for a phase transition to a new state of matter -- the Quark Gluon Plasma (QGP). In this paper, we report results on Lambda and Xi hyperon production in central Pb-Pb collisions at 160 GeV/c per nucleon beam momentum. 
G.E. Bruno (for the NA57 Collaboration)