PRODUCTION OF DEUTERONS AND PIONS IN A TRANSPORT MODEL OF ENERGETIC HEAVY-ION REACTIONS

Green functions are used to derive transport equations with bound-state production and absorption. The equations are valid in the quasiparticle limit and are used to describe deuteron production in heavy-ion induced reactions. The deuterons are produced in three-nucleon collisions in a process that is inverse to deuteron breakup. We also derive rate equations for pion production by resonance formation and decay. Our equations satisfy detailed balance even in the case of wide resonances, unlike previous formulations. The relation widely employed in the cascade and Boltzmann equation models produces an equilibrium with too many pions. We have solved the equations numerically, finding for a number of cases fair agreement with experimental data. The predicted entropy produced in central Nb + Nb collisions at 650 MeV/nucleon exceeds by half a unit the entropy deduced from data. The predicted pion yields in the cascade limit are much closer to the data measured in central Ar + KCl collisions than was found in earlier treatments.