Interactions of Pions in the CALICE Silicon-Tungsten Calorimeter Prototype

This paper presents a detailed study of hadronic interactions using data recorded with the highly granular CALICE silicon-tungsten electromagnetic calorimeter. Appoximately 750,000 selected $\pi^-$ at energies between 2 and 10 GeV have been studied. Using algorithms developed to identify the position of the first hadronic interaction within the calorimeter, the predictions of several physics models available within the GEANT4 simulation toolkit are compared to data. Although a good overall description of the data is observed, there are significant quantitative discrepancies in the longitudinal and transverse distributions of deposited energy.