Direct-simulation Monte Carlo models for high-energy inelastic processes

Abstract

Three Monte Carlo models are presented for providing descriptions of center-of-mass angular distributions, longitudinal and transverse momentum distributions, and effective-mass distributions for multiparticle final states produced in high-energy inelastic processes. They are applied specifically to the reaction pp → ppπ+π−, and the results are compared with experimental data for this reaction at incident-proton laboratory momenta of 22 GeV/c and 10 GeV/c. One of the models I involves a virtual dissociation of the target (projectile) into pπ+π− with projectile (target) involved only to the extent that its longitudinal momentum is reduced sufficiently to permit the target (projectile) associated pπ+π− to be freed in the final state with overall energy-momentum conservation. A second model II has the target (projectile) dissociating into pπ+ and the projectile (target) dissociating into pπ−. Both I and II include additional exchanged systems to provide transverse-momentum transfer from the target to projectile system. The last model III is based on a virtual dissociation of both target and projectile into a proton and another system (mass taken as zero). These two systems combine and decay into π+ and π−. It is shown that a particular combination of I and III provides a good qualitative description of the ppπ+π− data at both 10 GeV/c and 22 GeV/c.