  Monoenergetic antineutrinos emitted in the bound state beta-decay of H can be
resonantly captured in 3He. Favorable conditions are offered by tritide
technology for ultra sharp recoilless resonant capture of the 18.6 keV nubare
with sigma~5x10-32 cm2, 11 orders of magnitude larger than sigma(nubare +p).
The gravitational red shift of neutrinos and the mixing angle theta13 may be
measurable in bench scale baselines.

High Energy Physics - Phenomenology