Momentum Spectrum of Muons

Abstract

The momentum spectrum has been measured with a magnetic spectrometer for cosmic-ray particles incident vertically and at 68° zenith angle, in the range 2 to 70 Bev/c. The apparatus discriminates strongly against all particles but muons. The vertical muon spectrum is found to be in good agreement with the results reported by Pine et al. and by Ashton et al. No comparable data at 68° have been published. Assuming muon creation to occur entirely through pion decay, a single pion production spectrum accounts for the muon spectra at both zenith angles. The muon positive excess at energies of 8 to 50 Bev has also been obtained. The results, while in general agreement with those of other workers, confirm the expected tendency for the positive excess to decrease with energy.