The sun and its neutrinos

Neutrinos provide instant information on solar fusion reactions, the sources of solar energy. The reasons for the observed shortage by a factor of 3 in the high-energy portion of the solar neutrino flux are unknown at present. The European Gallex Collaboration will perform a solar neutrino experiment aiming at the low-energy portion of the solar neutrino spectrum, which is directly related to the known solar luminosity. Any deficit of solar neutrinos observed in the new experiments would be indicative of neutrino properties such as neutrino masses and neutrino mixing. (orig.)