PRODUCTION OF STRANGE PARTICLES IN PROTON-NUCLEUS AND NUCLEUS-NUCLEUSCOLLISIONS AT 200A-GEV

The production of strange particles at the energies of the SPS acceler ator at CERN is investigated in the model of quark-gluon strings. An a nalysis shows that the observed form of the rapidity and transverse-ma ss distributions of the particles is reproduced well by the model, for both peripheral and central collisions of heavy ions. However, in cen tral collisions the model underestimates the yield of strange particle s by factors of about 2:2:4 for K(S)0, LAMBDA and LAMBDABAR, respectiv ely. This discrepancy can be regarded as a possible manifestation of a collective interaction of strings like the formation of a ''color rop e.'' Predictions of the model are given for experiments with a beam of Pb ions, planned for the near future at CERN.