Hadron Production Model Developments and Benchmarking in the 0.7 - 12 GeV Energy Region

TL;DR

This paper presents recent improvements to the MARS15 event generator for hadron production modeling in the 0.7 to 12 GeV energy range, validated against extensive experimental data for better accuracy in high-intensity physics projects.

Contribution

The paper introduces new combined models for particle production in the 0.7-12 GeV range, integrating phase-space, isobar, and Quark-Gluon String models, with improved nuclear medium propagation and a two-source parameterization for large-angle pion production.

Findings

Models show good agreement with experimental data from CERN, JINR, LANL, BNL, and KEK.

Enhanced modeling of prompt particle production in nucleon-nucleon and pion-nucleon reactions.

Improved description of pion, kaon, and strange particle propagation in nuclear media.

Abstract

Driven by the needs of the intensity frontier projects with their Megawatt beams, e.g., ESS, FAIR and Project X, and their experiments, the event generators of the MARS15 code have been recently improved. After thorough analysis and benchmarking against data, including the newest ones by the HARP collaboration, both the exclusive and inclusive particle production models were further developed in the crucial for the above projects - but difficult from a theoretical standpoint - projectile energy region of 0.7 to 12 GeV. At these energies, modelling of prompt particle production in nucleon-nucleon and pion-nucleon inelastic reactions is now based on a combination of phase-space and isobar models. Other reactions are still modeled in the framework of the Quark-Gluon String Model. Pion, kaon and strange particle production and propagation in nuclear media are improved. For the alternative inclusive mode, experimental data on large-angle (> 20 degrees) pion production in hadron-nucleus interactions are parameterized in a broad energy range using a two-source model. It is mixed-and-matched with the native MARS model that successfully describes low-angle pion production data. Predictions of both new models are - in most cases - in a good agreement with experimental data obtained at CERN, JINR, LANL, BNL and KEK.