SOLUTIONS TO THE SOLAR-NEUTRINO ANOMALY

We present an updated analysis of astrophysical solutions, two-flavor MSW solutions, and vacuum oscillation solutions to the solar neutrino anomaly. The recent results of each of the five solar neutrino experim ents are incorporated, including both the zenith angle (day-night) and spectral information from the Kamiokande experiment, and the prelimin ary super-Kamiokande results. New theoretical developments include the use of the most recent Bahcall-Pinsonneault flux predictions (and unc ertainties) and density and production profiles, the radiative correct ions to the neutrino-electron scattering cross section, and new constr aints on the Ga absorption cross section inferred from the gallium sou rce experiments. From a model-independent analysis, arbitrary astrophy sical solutions are excluded at the 99.4% C.L. and more than 98% C.L. even if one ignores any one of the three classes of experiment, relaxe s the luminosity constraint, or allows more suppression of the Be-7 th an B-8 flux. The data are well described by large and small mixing ang le two-flavor MSW conversions, MSW conversions into a sterile neutrino with small mixing, or vacuum oscillations. We also present MSW fits f or nonstandard solar models parametrized by an arbitrary solar core te mperature or arbitrary B-8 flux. [S0556-2821(97)01422-7].