Fast Calorimeter Punch-Through Simulation for the ATLAS Experiment

This work discusses the parametrization, implementation and validation of a tuneable fast simulation of hadronic leakage in the ATLAS detector. It is dedicated to simulate calorimeter punch-through and decay in flight processes inside the ATLAS calorimeter. Both effects can cause systematic errors in muon reconstruction and identification. Therefore a correct description of these effects is crucial for many physics studies involving muons. The parameterized punch-through simulation is integrated into the fast ATLAS detector simulations Fatras and AtlfastII, respectively. The Fatras based simulation of single pions shows a good agreement with results obtained by the full Geant4 detector simulation – especially in the context of a fast simulation. It is shown that for high energy multi jet events, simulated with the AtlfastII implementation, the muon reconstruction rates show a good agreement with the Geant4 simulated reference.