The muon charge ratio at 80° to the zenith

Abstract

A brief description is given of a spectrograph recently constructed at Nottingham for the study of muons at large zenith angles. The instrument, situated at a latitude of 50 °N and 30 m above sea level, is at present orientated to accept muons incident in the geomagnetic north–south direction at a mean zenith angle of 80°. Experimental results are presented of the charge ratio among muons in the range of production energies 20–500 GeV. The results, which are found to be consistent with a constant or only slowly varying charge ratio over the entire energy range, are compared with the results of other workers and the predictions of some current theoretical models.