Imprint of SNO neutral current data on the solar neutrino problem

Abstract

We perform a global analysis in the framework of two active neutrino oscillations of all solar neutrino data, including the recent SNO day and night spectra (comprised of the charged current (CC), elastic scattering (ES) and neutral current (NC) events), the Super-Kamiokande (SK) day and night spectra (from 1496 days) and the updated SAGE results. We find that the Large Mixing Angle (LMA) solution is selected at the 99% C.L.; the best-fit parameters are Δm^2=5.6 \times 10^{-5} eV^2 and θ=32^{\circ}. No solutions with θ\geq π/4 are allowed at the 5σC.L. Oscillations to a pure sterile state are excluded at 5.3σ, but a sizeable sterile neutrino component could still be present in the solar flux.