Low $Q$ value weak nuclear decays are considered which have two-body final states (electron captures and bound-state beta decays). This opens the possibility for the observation of a process analogous to the Mössbauer effect, where the emitted (anti)neutrinos would be resonantly absorbed by atoms in a suitable absorber. Candidates for such a process are examined. Linewidths as small as the narrowest observed in Mössbauer spectroscopy may conceivably allow a new class of $\nu$ (disappearance) oscillation experiments.

NUCLEAR REACTIONS Discuss recoilless resonant neutrino absorption by nuclei.

• Received 24 June 1983

DOI:https://doi.org/10.1103/PhysRevC.28.2162