Electromagnetic interactions of high energy cosmic ray muons

• Main Author: Coats, R. B.
• Published: Durham University 1967
• Subjects: 531.16
• Online Access: http://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.585803

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.