The Event Generator DPMJET-III at Cosmic Ray Energies

A new version of the Monte Carlo event gener- ator DPMJET for air shower simulations is presented. It is a code system based on the Dual Parton Model and com- bines all features of the D TUNUC-2, DPMJET-II and PHOJET 1.12 event generators. DPMJET-III allows the simulation of hadron-hadron, hadron-nucleus, nucleus-nucleus, photon- hadron, photon-photon and photon-nucleus interactions from a few GeV up to the highest cosmic ray energies. Hadronic collisions at high energies involve the production of particles with low transverse momenta, the so-called soft multiparticle production. The theoretical tools available at present are not sufficient to understand this feature from QCD and phenomenological models are typically applied instead. The Dual Parton Model (DPM) (Capella et al., 1994) is such a model and its fundamental ideas are presently the basis of many of the Monte Carlo (MC) implementations of soft in- teractions in codes used for cosmic ray shower simulations. Many of these implementations are however limited in their application, for example with respect to the energy range or the collision partners (hadrons, nuclei, photons) which the model can be used for. In this paper we present the DPMJET-III code system, a MC event generator based on the DPM which is unique in its wide range of application. DPMJET-III is capable of simulat- ing hadron-hadron, hadron-nucleus, nucleus-nucleus, photon- hadron, photon-photon and photon-nucleus interactions from a few GeV up to the highest cosmic ray energies.