Measurement of day and night neutrino energy spectra at SNO and constraints on neutrino mixing parameters -: art. no. 011302

The Sudbury Neutrino Observatory (SNO) has measured day and night solar neutrino energy spectra and rates. For charged current events, assuming an undistorted B-8 spectrum, the night minus day rate is 14.0%+/-6.3%(+1.5)(-1.4) % of the average rate. If the total flux of active neutrinos is additionally constrained to have no asymmetry, the nu(e) asymmetry is found to be 7.0%+/-4.9%(+1.3)(-1.2)% . A global solar neutrino analysis in terms of matter-enhanced oscillations of two active flavors strongly favors the large mixing angle solution.