Electromagnetic interactions of high energy cosmic my muons

Abstract

Electromagnetic interactions of high energy muons incident in the nearly horizontal direction at Durham, I98 ft. above sea level, have been studied by detecting electron-photon bursts produced in iron absorbers. Over the measured burst size range, bremsstrahlung and knock-on electron production were the predominant energy transfer processes. No divergence from accepted theory has been observed for energy transfer in the range 3 - 240 GeV. A second burst experiment has been performed to measure the spectra of nuclear-active particles incident at Durham in the nearly vertical direction. The observed spectra of both charged and neutral nuclear-active particles show a discontinuity at energies >100 GeV, which can be taken as support for the SU(_3) prediction that a protonis a tightly bound system of three charged quarks. This interpretation would indicate a quark mass of 10 GeV, and that high energy protons dissociate into their constituent quarks in about l8^ of their collisions above threshold (18OO GeV). A further implication isthat quarks interact strongly in the atmosphere, otherwise telescope detectors would have recorded an abundance of quarks. A decrease-2in the nucleon attenuation length from 127 gm. cm to a value ofp117 gm. cm(^-2) for sea level nucleon energies > 100 GeV would also account for the observed discontinuity.