New Tools for Solving the Solar-Neutrino Problem

Neutrino (ν) excitation of nuclear levels (NUEX) via neutral currents is shown to be crucially important to the solar-ν problem as a method of detecting ν's regardless of flavor. We examine ¹¹B, ⁴⁰Ar, and ³⁵Cl as NUEX targets. The ¹¹B system offers means for concurrent solar-ν spectroscopy by NUEX and by charged-current νₑ capture with a set of differing thresholds. It promises a self-contained solution to the solar-ν problem as well as key probes for revealing the structure of resonant flavor and nonflavor ν oscillations in the sun. This approach may be feasible in an ICARUS-type underground experiment.