Johannes Ranft

The Monte Carlo Event Generator DPMJET-III

A new version of the Monte Carlo event generator Dpmjet is presented. It is a code system based on the Dual Parton Model and unifies all features of the Dtunuc-2, Dpmjet-II and Phojet1.12 event generators. Dpmjet-III allows the sim- ulation 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) (1) is such a model and its fundamental ideas are presently the basis of many of the Monte Carlo (MC) implementations of soft interactions in codes used for Radiation Physics simulations. Many of these implementations are however limited in their application by, for example, the collision energy range which they are able to describe or by the collision partners (hadrons, nuclei, photons) which the model can be used for. With respect to modern multi-purpose codes for particle interaction and transport these limitations at high energy are clearly often a disadvantage. 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 simulating 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. In the present paper we give an overview over the different components and models of Dpmjet-III and present a few examples for comparisons of model results with experimental data.

Charm production in DPMJET

In this work, charm production in the DPMJET hadronic jet simulation is compared to experimental data. Since the major application of DPMJET is the simulation of cosmic-ray-induced air showers, the version of the code integrated in the CORSIKA simulation package has been used for the comparison. Wherever necessary, adjustments have been made to improve agreement between simulation and data. With the availability of new muon/neutrino detectors that combine a large fiducial volume with large amounts of shielding, investigation of prompt muons and neutrinos from cosmic ray interactions will be feasible for the first time. Furthermore, above TeV charmed particle decay becomes the dominant background for diffuse extraterrestrial neutrino flux searches. A reliable method to simulate charm production in high-energy proton–nucleon interactions is therefore required.

The hadronic models for cosmic ray physics: the FLUKA code solutions

FLUKA is a general purpose Monte Carlo transport and interaction code used for fundamental physics and for a wide range of applications. These include Cosmic Ray Physics (muons, neutrinos, EAS, underground physics), both for basic research and applied studies in space and atmospheric flight dosimetry and radiation damage. A review of the hadronic models available in FLUKA and relevant for the description of cosmic ray air showers is presented in this paper. Recent updates concerning these models are discussed. The FLUKA capabilities in the simulation of the formation and propagation of EM and hadronic showers in the Earth’s atmosphere are shown.

Heavy-ion collisions: preliminary results of a new QMD model coupled with FLUKA

Quantum Molecular Dynamics (QMD) models are considered viable tools to simulate the initial hot stages of heavy-ion collisions and investigate the properties of the nuclear matter equation of state. A new QMD model has been developed by scratch by our group during the last few years and recently coupled to the FLUKA fission/Fermi breakup/ evaporation module which describes the latest stage of the reactions, when slower processes leading nuclei to the equilibrium occur. Comparisons with experimental data collected both in symmetric and in asymmetric collisions are shown, covering a wide range of projectile and target masses. Reproduction of the experimental light particle (Z < 3) yields is one of the most difficult challenges to be met by QMD models, traditionally prone to underestimate a particle emission while dramatically overestimating proton and neutron emission. Our results seem to be quite satisfactory with respect to this issue, thanks to the form of the potential terms involved in the nucleon-nucleon interaction and to many refinements applied in the fragment definition scheme, based on the potential which each particle experiences because of its neighbors. Nucleon isospin is taken into account all over the simulation, as well as the experimental binding energy constraints on nuclear states. The introduction of further refinements to describe pre-equilibrium processes is under development.

Comparison of measurements of angular hadron energy spectra, induced activity and dose with FLUKA82 calculations

Abstract Three experiments are described in which extended targets were bombarded with high-energy protons. The experiments were simulated using the Monte Carlo hadron cascade package FLUKA82. The measured and simulated quantities included the hadron yield around a target as a function of polar angle and energy and the two-dimensional ( r − z ) distributions of stars and energy deposition inside an aluminium cylinder. The agreement between the calculations and measurements is generally within experimental errors.

Gamma-gamma physics at LEP2

This report is an overview of the gamma-gamma physics capabilities of LEP2, and covers the following topics: structure functions, equivalent photon approximation, tagging conditions etc, soft and semihard physics, large-

Hadron production simulation by FLUKA

p_t

High energy hadron production Monte Carlos

processes, heavy-quark physics, and exclusive channels.

Towards a Comprehensive Description of Heavy Ion Reactions

For the purposes of accelerator based neutrino experiments, the simulation of parent hadron production plays a key role. In this paper a quick overview of the main ingredients of the PEANUT event generator implemented in the FLUKA Monte Carlo code is given, together with some benchmarking examples.

Progress towards a FLUKA based simulation tool aimed at the evaluation of space radiation environments

We discuss here Quantum molecular dynamics models (QMD) and Dual Parton Models (DPM and QGSM). We compare RHIC data to DPM‐models and we present a (Cosmic ray oriented) model comparison.We discuss here Quantum molecular dynamics models (QMD) and Dual Parton Models (DPM and QGSM). We compare RHIC data to DPM--models and we present a (Cosmic ray oriented) model comparison.