POINCARE COVARIANT PARTICLE DYNAMICS .1. INTRANUCLEAR CASCADE MODEL

To analyze the high energy heavy ion reactions performed at Lawrence B erkeley BEVALAC, Brookhaven AGS, and CERN SPS we present a dynamical m odel that is entirely Poincare covariant. The description of strong in teractions by Lorentz-scalar quasipotentials makes possible a relativi stic extension of the cascade concept without losing its inherent simp licity. No field degrees of freedom appear explicitly, neither in elas tic nucleon scattering nor in particle creation processes. Although va rious formalisms describe directly interacting relativistic particles with identical solutions for the two-particle case, they all suffer fr om different problems in many-particle systems. The basis of our appro ach is a Hamiltonian formulation for N pointlike nucleons, moving unco nstrained in an 8N-dimensional phase space. One additional Lorentz sca lar is introduced for an appropriate parametrization of all trajectori es, defining also the connection to the proper times of the individual interacting nucleons. The creation of particles, for which Hamiltonia n dynamics does not provide a generic mechanism, is incorporated pheno menologically as a ''perturbative'' process. We describe heavy ion col lisions as a sequence of two-particle reactions without any additional fit to experimental data. Pion yield and mass spectra of the heavy fr agments agree reasonably well with BEVALAC results. We do not compare to experimental high energy data because the employed mechanism of par ticle production is certainly improper in that regime. However, the nu merical results give an impression on how the reaction evolves.