Implications of Solar Neutrino Experiments

All four solar neutrino experiments observe a deficit of solar neutrinos compared to the predictions of the standard solar model. More significant, any two of the three classes of experiments indicate that the largest suppression is in the middle of the spectrum (the Be-7 line and the lower energy part of the B-8 spectrum). Astrophysical and nuclear physical explanations generally predict that the largest suppression should be of the B-8 neutrinos (since they are made after and from Be-7) and that the B-8 spectrum is not significantly distorted. Thus, unless most of the experiments are wrong or exhibit very large statistical fluctuations, a solution based on neutrino properties, such as MSW matter-enhanced conversions or vacuum oscillations is favored. The next generation should be able to confirm or falsify these ideas, essentially free of astrophysical uncertainties. With or without new neutrino properties, the solar neutrinos are and will be an important probe of the core of the sun.

Naoya Hata (; Paul Langacker (