Geant4 physics validation for large HEP detectors

Optimal exploitation of hadronic final states played a key role in successes of all recent collider experiment in HEP, and the ability to use hadronic final states will continue to be one of the decisive issues during the analysis phase of the LHC experiments. Carlo techniques facilitate the use of hadronic final states, and have been developed for many years. We will give a brief overview of the physics underlying hadronic shower simulation, discussing the three basic types of modeling; data-driven, parametrization-driven, and theory-driven modeling at the example of geant4. We will confront these different types of modeling with the stringent requirements posed by the LHC experiments on hadronic shower simulation, and report on the current status of the validation effort for large HEP applications. We will address robustness, and CPU and physics performance evaluations.