Solar neutrinos: the SNO salt phase results and physics of conversion

Original · EN

We have performed analysis of the solar neutrino data including results from the SNO salt phase as well as the combined analysis of the solar and the KamLAND results. The best fit values of neutrino parameters are Delta m² = 7.1e-5 eV², tan²θ= 0.40 with the boron flux fB = 1.04. New SNO results strongly disfavor maximal mixing and the h-LMA region (Delta m² > 1e-4 eV²) which is accepted now at the 3-sigma level. We find the 3-sigma upper bounds: Delta m² < 1.7e-4 eV² and tan²θ< 0.64, and the lower bound Delta m² > 4.8e-5 eV². Non-zero 13-mixing does not change these results significantly. The present data determine quantitatively the physical picture of the solar neutrino conversion. At high energies relevant for SNO and Super-Kamiokande the deviation of the effective survival probability from the non-oscillatory value is about 10 - 14%. The oscillation effect contribution to this difference about 10% and the Earth regeneration is about 3 - 4%. At low energies (E < 1 MeV) the matter corrections to vacuum oscillation effect are below 5%. The predictions for the forthcoming measurements are given which include the spectral distortion and CC/NC ratio at SNO, the Day-Night asymmetry, the KamLAND spectrum and rate.