Solar neutrinos: Global analysis with day and night spectra from SNO

We perform global analysis of the solar neutrino data including the day and night spectra of events at SNO. In the context of two active neutrino mixing, the best fit of the data is provided by the large-mixing angle (LMA) Mikheyev-Smirnov-Wolfenstein solution with Deltam(2)=6.15x10(-5) eV(2), tan(2)theta=0.41, f(B)=1.05, where f(B) is the boron neutrino flux in units of the corresponding flux in the standard solar model (SSM). At the 3sigma level we find the following upper bounds: tan(2)theta<0.84 and Delta m(2)<3.6x10(-4) eV(2). From a 1 sigma interval we expect the day-night asymmetries of the charged current and electron scattering events to be A(DN)(CC)=3.9(-2.9)(+3.6)% and A(DN)(ES)=2.1(-1.4)(+2.1)%. The only other solution which appears at the 3sigma level is the VAC solution with Deltam(2)=4.5x10(-10) eV(2), tan(2)theta=2.1, and f(B)=0.75. The best fit point in the low probability, low mass region, with Deltam(2)=0.93x10(-7) eV(2) and tan(2)theta=0.64, is accepted at 99.95% (3.5sigma) C.L. The least chi(2) point from the small mixing angle solution region, with Deltam(2)=4.6x10(-6) eV(2) and tan(2)theta=5x10(-4), could be accepted at the 5.5sigma level only. In the three neutrino context the influence of theta(13) is studied. We find that with an increase of theta(13) the LMA best fit point shifts to a larger Deltam(2), the mixing angle is practically unchanged, and the quality of the fit becomes worse. The fits of LOW and SMA slightly improve. Predictions for the KamLAND experiment (total rates, spectrum distortion) have been calculated.