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 $\Delta m^2=6.15\mathrm{}\times {10}^{-5}{\mathrm{eV}}^2,{\tan }^2\theta =0.41,f_B=1.05,$ where $f_B$ is the boron neutrino flux in units of the corresponding flux in the standard solar model (SSM). At the $3\sigma$ level we find the following upper bounds: ${\tan }^2\theta <0.84\mathrm{}$ and $\Delta m^2<3.6\mathrm{}\times {10}^{-4}{\mathrm{eV}}^2.$ From a $1\sigma$ interval we expect the day-night asymmetries of the charged current and electron scattering events to be $A_{\mathrm{DN}}^{\mathrm{CC}}{=3.9\mathrm{}}_{-2.9}^{+3.6\mathrm{}}\%$ and $A_{\mathrm{DN}}^{\mathrm{ES}}{=2.1\mathrm{}}_{-1.4}^{+2.1\mathrm{}}\%.\mathrm{}$ The only other solution which appears at the $3\sigma$ level is the VAC solution with $\Delta m^2=4.5\mathrm{}\times {10}^{-10}{\mathrm{eV}}^2,$ ${\tan }^2\theta =2.1,$ and $f_B=\mathrm{0.75.}\mathrm{}$ The best fit point in the low probability, low mass region, with $\Delta m^2=0.93\mathrm{}\times {10}^{-7}{\mathrm{eV}}^2$ and ${\tan }^2\theta =0.64,$ is accepted at 99.95% $\left(3.5\mathrm{}\sigma \right)$ C.L. The least ${\chi }^2$ point from the small mixing angle solution region, with $\Delta m^2=4.6\mathrm{}\times {10}^{-6}{\mathrm{eV}}^2$ and ${\tan }^2\theta =5\mathrm{}\times {10}^{-4},$ could be accepted at the $5.5\sigma$ level only. In the three neutrino context the influence of ${\theta }_{13}$ is...