A measurement of the atmospheric neutrino flux and oscillation parameters at the Sudbury Neutrino Observatory

Abstract

Through-going muon events are analyzed as a function of their direction of travel through the Sudbury Neutrino Observatory. Based on simulations and previous measurements, muons with a zenith angle of 1 < cos([theta]zenith) < 0:4 are selected as atmospheric neutrino-induced muons. A two-neutrino analysis of these events agrees with the oscillation parameters observed by the Super Kamiokande and Minos experiments, and places 2-D limits of [delta]m2 23 = 1:8+7:1 ??1:1 103 eV2 at the 68% confidence level, and sin2(2[theta]23) > 0:33 at the 90% confidence level. In addition, the flux of atmospheric neutrinos is measured in 1-D with a 68% confidence level to be 1:24+0:11 0:10 times the prediction of the BARTOL group based on SNO data alone, and 1:27+/-0.09 times the prediction when the oscillation parameters are constrained by the Super Kamiokande and Minos results.