An investigation into the electron-proton discrimination capabilities of ionization calorimeters

Abstract

This paper seeks to provide an experimental indication of the rate at which protons mimic electrons in ionization calorimeters. A pseudo-theoretical electron cascade function was fitted to calorimeter events caused by 300 GeV accelerator protons in order to see what fraction of the protons looked like electrons. For calorimeters longer than one nuclear interaction length, the results were in good agreement with the theory which says that only one process should make a significant contribution to the mimicking of electrons by protons: the diffractive excitation of the incident proton, producing a π 0 while the incident proton continues on undeflected without further interactions. For calorimeters shorter than one nuclear interaction length a much higher mimic rate was seen, which is to be expected since hadrons produced with a π 0 can easily pass undetected through the calorimeter. These results can be used to estimate the contamination of the data of past experiments and as support for the predictions being used to design future experiments.