Exploring the structure of hadronic showers and hadronic energy reconstruction with highly granular calorimeters

The CALICE Collaboration pioneers past and present developments of highly granular calorimeters. The prototypes provide unprecedented 3D images of hadronic showers with up to 500000 cells. This article presents highlights of the physics results of the CALICE research programme in terms of energy reconstruction of hadronic showers via software compensation and the analysis of fine details of hadronic showers that are uniquely accessible because of the high granularity. The high granularity in combination with different absorber and sensitive materials lead to a deep understanding of hadronic showers. This is valuable input to the improvement of simulation models of hadronic showers e.g. as implemented in the simulation toolkit GEANT4. The data were recorded with the different prototypes since 2005 at the beam test facilities of CERN and FNAL.