Transition between hadronic models in Geant4

Abstract

Transportation codes for medium- and high-energy applications need to simulate hadronic interactions in a wide energy range, typically from MeV to hundreds of GeV. Yet the range of applicability of detailed hadronic models usually spans more limited kinematic regions. Therefore, different models are combined in order to address the full spectrum of hadronic collisions. We present an overview of the transitions between hadronic models in Geant4, with the emphasis on configurations (Physics Lists) relevant to applications in LHC experiments. Unphysical discontinuities in calorimeter observables have been reported by ATLAS and CMS collaborations in the transition regions between hadronic models. We have investigated the microscopic origin of these effects, and present the first improvements in the energy dependence of key physical observables in Geant4 simulations.