Solution of the solar-neutrino problem

Comparison of the results from the Kamiokande neutrino-electron scattering experiment with those from the chlorine experiment and with solar models shows that the explanation of the solar-neutrino problem probably requires physics beyond the standard electroweak model with zero neutrino masses. The experimental results, including the shape of the electron-recoil energy spectrum measured by Kamiokande, are in excellent agreement with a nonadiabatic solution of the Mikheyev-Smirnov-Wulfenstein effect, yielding a neutrino mass difference of Δ${\mathit{m}}^2$=1×${10}^{\mathrm{-}8}$ ${\sin }^{\mathrm{-}2}$ ${\mathrm{\Theta }}_{\mathit{V}}$ ${\mathrm{eV}}^2$.