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

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 m^2 = 7.1e-5 eV^2, tan^2\theta = 0.40 with the boron flux f_B = 1.04. New SNO results strongly disfavor maximal mixing and the h-LMA region (Delta m^2 > 1e-4 eV^2) which is accepted now at the 3-sigma level. We find the 3-sigma upper bounds: Delta m^2 < 1.7e-4$ eV^2 and tan^2\theta < 0.64, and the lower bound Delta m^2 > 4.8e-5 eV^2. 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.Comment: figures and some numbers corrected, discussion of coherence loss added, number of pages slightly change

Large mixing angle solution to the solar neutrino problem and random matter density perturbations

There are reasons to believe that mechanisms exist in the solar interior which lead to random density perturbations in the resonant region of the Large Mixing Angle solution to the solar neutrino problem. We find that, in the presence of these density perturbations, the best fit point in the (sin^2(2\theta), Delta_m^2) parameter space moves to smaller values, compared with the values obtained for the standard LMA solution. Combining solar data with KamLAND results, we find a new compatibility region, which we call VERY-LOW LMA, where sin^2(2\theta) ~ 0.6 and Delta_m^2~2e-5 eV^2, for random density fluctuations of order 5% < \xi< 8%. We argue that such values of density fluctuations are still allowed by helioseismological observations at small scales of order 10 - 1000 km deep inside the solar core.Comment: References and discussion added, with some small numerical corrections implemente

Non-standard neutrinos interactions in a 331 model with minimum Higgs sector

We present a detailed analysis of a class of extensions to the SM Gauge chiral symmetry $SU(3)_{C}\times SU(3)_{L}\times U(1)_{X}$ (331 model), where the neutrino electroweak interaction with matter via charged and neutral current is modified through new gauge bosons of the model. We found the connections between the non-standard contributions on 331 model with non-standard interactions. Through limits of such interactions in cross section experiments we constrained the parameters of the model, obtaining that the new energy scale of this theory should obey $V>1.3$ TeV and the new bosons of the model must have masses greater than 610 GeV.Comment: 17 Pages, latex, 1 Table

Effects of magnetohydrodynamics matter density fluctuations on the solar neutrino resonant spin-flavor precession

Taking into account the stringent limits from helioseismology observations on possible matter density fluctuations described by magnetohydrodynamics theory, we find the corresponding time variations of solar neutrino survival probability due to the resonant spin-flavor precession phenomenon with amplitude of order O(10%). We discuss the physics potential of high statistics real time experiments, like as Superkamiokande, to observe the effects of such magnetohydrodynamics fluctuations on their data. We conclude that these observations could be thought as a test of the resonant spin-flavor precession solution to the solar neutrino anomaly.Comment: 16 pages, 3 figure

Seasonal Dependence in the Solar Neutrino Flux

MSW solutions of the solar neutrino problem predict a seasonal dependence of the zenith angle distribution of the event rates, due to the non-zero latitude at the Super-Kamiokande site. We calculate this seasonal dependence and compare it with the expectations in the no-oscillation case as well as just-so scenario, in the light of the latest Super-Kamiokande 708-day data. The seasonal dependence can be sizeable in the large mixing angle MSW solution and would be correlated with the day-night effect. This may be used to discriminate between MSW and just-so scenarios and should be taken into account in refined fits of the data.Comment: 4 pages, latex, RevTeX, two postscript figure