STRANGE PARTICLE-PRODUCTION IN ULTRARELATIVISTIC HEAVY-ION COLLISIONSAT THE CERN SPS

The present status of experimental studies of strange particle product ion in ultrarelativistic heavy ion collisions at the CERN SPS is revie wed. The momentum spectra of strange particles indicate approximate ki netic equilibrium with non-strange particles. A strangeness enhancemen t by roughly a factor of 2 is observed with respect to nucleon-nucleon and nucleon-nucleus collisions. Neither hadron-resonance-gas models n or models incorporating an initial quark-gluon plasma phase have so fa r been able to quantitatively describe the data.