What will the first year of SNO show?

The ratio of the measured to the predicted standard model CC event rates in SNO will be 0.47 if no oscillations occur. The best-fit active oscillation predictions for the CC ratio are: 0.35-39 (MSW) and 0.38-42 (vacuum) (all for a 5 MeV energy threshold), typically about 20% less than the no-oscillation expectation. We calculate the predicted ratios for six active and sterile neutrino oscillation solutions allowed at 99% CL and determine the dependence of the ratios on energy threshold. If the high-energy anomaly observed by SuperKamiokande is due to an enhanced hep flux, MSW active solutions predict that out of a total of 5000 CC events above 5 MeV in SNO between 49 and 54 events will be observed above 13 MeV whereas only 19 events are expected for no-oscillations and a nominal standard hep flux.Comment: Phys Lett accepted. Editorial corrections. Related material and viewgraphs at http://www.sns.ias.edu/~jn

Electron capture on ^{8}B nuclei and Superkamiokande results

The energy spectrum of recoil electrons from solar neutrino scattering, as observed by Superkamiokande, is deformed with respect to that expected from SSM calculations. We considered \nu-e scattering from neutrinos produced by the electron-capture on ^{8}B nuclei, e^{-}+^{8}B --> ^{8}Be^{*}+\nu_{e}, as a possible explanation of the spectral deformation. A flux \Phi_{eB}\simeq 10^{4} cm^{-2} s^{-1} could account for Superkamiokande solar neutrino data. However this explanation is untenable, since the theoretical prediction, \Phi_{eB}=(1.3+-0.2) cm^{-2} s^{-1}, is smaller by four orders of magnitude.Comment: 9 pages, incl. 3 figures (epsfig

Neutrino Mixing and Future Solar Neutrino Experiments

Possibilities of a model independent treatment of the data from future real-time solar neutrino experiments (SNO, Super-Kamiokande and others) are discussed. It is shown that in the general case of transitions of the initial solar $\nu_e$'s into $\nu_\mu$ and/or $\nu_\tau$ the total flux of initial 8B neutrinos and the $\nu_e$ survival probability can be determined directly from the experimental data. Lower bounds for the probability of transition of solar $\nu_e$'s into all possible sterile states are derived and expressed through measurable quantities.Comment: 3 pages. Compressed postscript file. If you prefer the uncompressed postscript file or a hardcopy of the paper, please write to [email protected]. Talk presented by S.M. Bilenky at TAUP93. DFTT 66/9

A Mixed Solar Core, Solar Neutrinos and Helioseismology

We consider a wide class of solar models with mixed core. Most of these models can be excluded as the predicted sound speed profile is in sharp disagreement with helioseismic constraints. All the remaining models predict $^7$Be and/or $^7$B neutrino fluxes at least as large as those of SSMs. In conclusion, helioseismology shows that a mixed solar core cannot account for the neutrino deficit implied by the current solar neutrino experiments.Comment: 6 pages, RevTeX, plus 5 postscript figure

Present Status of the Theoretical Predictions for the ^(37)Cl Solar-Neutrino Experiment

The theoretical predictions for the ^(37)Cl solar-neutrino experiment are summarized and compared with the experimental results of Davis, Harmer, and Hoffman. Three important conclusions about the sun are shown to follow

Solar Neutrinos

Experimental work with solar neutrinos has illuminated the properties of neutrinos and tested models of how the sun produces its energy. Three experiments continue to take data, and at least seven are in various stages of planning or construction. In this review, the current experimental status is summarized, and future directions explored with a focus on the effects of a non-zero theta-13 and the interesting possibility of directly testing the luminosity constraint. Such a confrontation at the few-percent level would provide a prediction of the solar irradiance tens of thousands of years in the future for comparison with the present-day irradiance. A model-independent analysis of existing low-energy data shows good agreement between the neutrino and electromagnetic luminosities at the +/- 20 % level.Comment: 16 pages, 8 figures. Proceedings of International School on Nuclear Physics; 27th Course: "Neutrinos in Cosmology, in Astro, Particle and Nuclear Physics" in Erice, Sicily, Italy; September 16 - 24, 2005. To be published in Progress Part. Nucl. Phy

Direct determination of the solar neutrino fluxes from solar neutrino data

We determine the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian approach we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. This is done by means of a Markov Chain Monte Carlo employing the Metropolis-Hastings algorithm. We also describe how these results can be applied to test the predictions of the Standard Solar Models. Our results show that, at present, both models with low and high metallicity can describe the data with good statistical agreement.Comment: 24 pages, 1 table, 7 figures. Acknowledgments correcte