Measurement of the cosmic ray and neutrino-induced muon flux at the Sudbury neutrino observatory

Results are reported on the measurement of the atmospheric neutrino-induced muon flux at a depth of 2 kilometers below the Earth's surface from 1229 days of operation of the Sudbury Neutrino Observatory (SNO). By measuring the flux of through-going muons as a function of zenith angle, the SNO experiment can distinguish between the oscillated and unoscillated portion of the neutrino flux. A total of 514 muonlike events are measured between -1 < cos theta(zenith)< 0.4 in a total exposure of 2.30x10(14) cm(2) s. The measured flux normalization is 1.22 +/- 0.09 times the Bartol three-dimensional flux prediction. This is the first measurement of the neutrino-induced flux where neutrino oscillations are minimized. The zenith distribution is consistent with previously measured atmospheric neutrino oscillation parameters. The cosmic ray muon flux at SNO with zenith angle cos theta(zenith)> 0.4 is measured to be (3.31 +/- 0.01(stat)+/- 0.09(sys))x10(-10) mu/s/cm(2).