New prospects for real-time spectroscopy of low energy electron neutrinos from the sun

Flavor-specific real-time spectroscopy of solar electron neutrinos (nu(e)) from the p + p, Be-7 + e(-) and CNO reactions in the Sun may become practical for the first time nu a newly discovered class of nu(e) reactions. Highly specific signatures of nu(e) capture by the targets Yb-176, Gd-160, or Se-82 can discriminate against a background similar to 10(7) times larger than the nu(e) signals. A high-quality liquid scintillator containing up to similar to 15 wt% Yb has been developed for observing these nu(e) reactions. Experiments based on the new approach can, in principle, resolve basic puzzles set by current solar neutrino results and the underlying question of nu(e)-flavor conversion.