SOLAR NEUTRINOS

Solar neutrinos have been measured by a radioactive scheme involving ³⁷Cl, and by electron collisions at Kamiokande II. The former experiment gave 1/4, the latter 1/2 of the intensity expected from the standard solar model. Kamiokande showed that the central temperature from the standard model is at least approximately correct. Both experiments can be explained by the Mikheyev-Smirnov-Wolfenstein (MSW) theory, and they show the mass of the μ neutrino to be of order 10⁻³eV. Preliminary results from an experiment using ⁷¹Ga confirm the conclusions.