The direct production of electron pairs by high-energy muons underground (148 m w.e.)

Abstract

Direct production of electron pairs in thin iron targets by muons of mean energy 32.6 GeV was studied with a multiplate cloud chamber at a depth of 148 m w.e underground. Showers of two or more electrons associated with each outgoing muon from the targets were selected and their energy distribution determined for the target thicknesses 0.54 and 1.6 cm. The cross-sections for direct pair production of electrons as obtained from events produced in both thick and thin targets agree satisfactorily with those given by the Murota-Ueda-Tanaka theory in the ranges of energy-transfer (35÷100), (100÷500) and (500÷1000) MeV.