Recent developments in Geant4 hadronic physics

Geant4 is a software toolkit for the simulation of the passage of particles through matter. It is used in various application domains, including high energy physics, astrophysics and space science, and medical physics. The simulation of hadronic showers requires simulation of particles interacting over a wide range of energy, from a few TeV down to thermal energies. Models for hadronic interactions typically are only valid for a part of this energy range, or for a subset of particles. Thus there is a need to combine several models to cover the full energy range for all particles. This configuration of models is handled in a physics list. We will present an overview of recent developments in hadronic models and cross sections of Geant4 as well as revised physics lists. These developments were motivated by a need to improve the shape of hadronic showers for LHC experiments and to improve linearity of response in the energy region where we switch between models. The model developments were guided by a validation of simulation results against thin target data. Cross sections used were also checked and revised. Physics lists were adapted to use the improved models and cross sections. All of these improvements led to a change of the recommended physics list for LHC experiments from QGSP_BERT to FTFP_BERT.