ENHANCEMENT OF K+ PI(+) RATIO IN CENTRAL COLLISIONS BETWEEN HEAVY-NUCLEI/

The relativistic Vlasov-Uehling-Uhlenbeck model has been generalized t o identify the isospin degree of freedom of particles and used to simu late the particle production in Au+Au collisions at 1 GeV/nucleon. The calculated results describe very well the experimentally measured fea tures for the momentum spectra of proton, pi(+) and K+ particles, the multiplicities of pi(+) and K+, and the K+/pi(+) ratio as a function o f the number of participating nucleons. The physical origin of the sig nificant rise of The K+/pi(+) ratio when going from peripheral to cent ral collisions is also analysed.