Imaging Pion Showers with the CALICE Analogue Hadron Calorimeter

The CALICE collaboration investigates different technology options for highly granular calorimeters for detectors at a future electron-positron collider. One of the devices constructed and tested by the collaboration is a 1 m^3 prototype for an imaging scintillator-steel sampling calorimeter for hadrons with analogue readout (AHCAL). The light from 7608 small scintillator cells is detected with silicon photomultipliers. The AHCAL has been successfully operated during electron and hadron test-beam measurements at DESY, CERN, and Fermilab since 2005. The collected data allow for evaluating the novel technologies employed. In addition, these data provide a valuable basis for validating pion cascade simulations. This paper presents the current status of comparisons between the AHCAL data and predictions from different Monte Carlo models implemented in GEANT4. The comparisons cover the total visible energy, longitudinal and radial shower profiles, and the shower substructure. Furthermore, this paper discusses a software compensation algorithm for improving the energy resolution of the AHCAL for single pions.