Validation of Geant4 Physics Models with LHC Collision Data

The CMS experiment has designed a strategy to validate Geant4 physics models using collision data from the LHC. Isolated charged particles are measured simultaneously in the tracker as well as the calorimeters. These events are selected using dedicated triggers and are used to measure the response in the calorimeter. Measurements of mean response, resolution, energy sharing between the electromagnetic and hadron calorimeters, shower shapes are directly compared with predictions from the various physics models in the Geant4 description. The broad range of energies available in collision data allows stringent tests of the accuracy of the models in reproducing the observed distributions.