Reconciling the time dependence of the chlorine and Kamiokande solar-neutrino data

We present a detailed analysis of the effect of a large transition magnetic moment of the electron neutrino (i.e., ${\mu }_{{\nu }_e}\approx {10}^{-11\mathrm{}}{\mu }_B$) on the solar-neutrino flux measured in the chlorine and Kamiokande experiments. For $\Delta m_{{\nu }_{\mu }-{\nu }_e}^2\approx {10}^{-8\mathrm{}}$ e${\mathrm{V}}^2$ and ${\mu }_{\nu }\approx {10}^{-11\mathrm{}}{\mu }_B$, the combination of matter effects and spin precession enables us to explain the apparent anticorrelation of the neutrino flux with the sun-spot activity in the chlorine experiment, as well as the lack of time variation in the Kamiokande experiment. For this choice of parameters, we predict that the gallium experiment should show strong anticorrelation with the solar activity, with a maximum flux of 80 SNU (solar-neutrino units) during the Sun-spot minimum