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 Δm2=1x10-8 sin-2ΘV eV2