Extension of the Liège intranuclear cascade model at incident energies between 2 and 12 GeV. Aspects of pion production

The validity of the standard version of the Liège Intra-Nuclear Cascade (INCL4) model, which has been shown to be quite successful for the description of spallation reactions, is limited to an upper incident energy of ∼2 GeV, because inelastic elementary processes are restricted to the excitation and de-excitation of the Delta resonance. In this paper, the INCL4 model is extended to higher incident energy by including other inelastic elementary collisions. However, excitation of heavier baryonic resonances is replaced by direct multipion production in elementary nucleon–nucleon and pion–nucleon collisions. The predictions of the modified model for production of charged pions by proton and pion beams off nuclei are compared with experimental data of the HARP Collaboration for beam energies between 2 and 12 GeV. The apparent duality between the approach based on excitation of numerous baryonic resonances and our approach is briefly discussed.