ULTRARELATIVISTIC CASCADES AND STRANGENESS PRODUCTION

A two-phase cascade code, LUCIFER II [1], developed for the treatment of ultra high energy ion-ion collisions is applied to the production o f strangeness at SPS energies root s = 17 - 20. This simulation is abl e to simultaneously describe both hard processes such as Drell-Yan and slower, soft processes such as the production of light mesons by sepa rating the dynamics into two steps, a fast cascade involving only the nucleons in the original colliding relativistic ions followed, after a n appropriate delay, by a normal multiscattering of the resulting exci ted baryons and mesons produced virtually in the first step. No energy loss can take place in the short time interval over which the first c ascade takes place. The chief result is a reconciliation of the import ant Drell-Yan measurements with the apparent success of standard casca des to describe the nucleon stopping and meson production in heavy-ion experiments at the CERN SPS.