A novel way of electron identification in calorimeters

We show that electromagnetic and hadronic showers can be distinguished through differences in the time structure of the calorimeter signals. These differences occur at the level of 5–10 ns. It is experimentally observed that with a detector that is sufficiently fast, i.e. the scintillating fibre calorimeter developed in the framework of the LAA project at CERN, e/π separation can be achieved at the 1% level, independent of any knowledge of the shower profile.