We have measured the cosmic-ray muon charge ratio, $\frac{{\mu }^{+}}{{\mu }^{-}}$, from 10 GeV to 1.5 TeV with a sea-level magnetic spectrometer at eight different zenith angles between 0° and 90°. The data are consistent with a constant charge ratio between 50 GeV and 1.5 TeV, in agreement with the predictions of the scaling hypothesis. Assuming the charge ratio to be constant, we obtain its value as 1.261 ± 0.009.

• Received 12 March 1973

DOI:https://doi.org/10.1103/PhysRevLett.30.937