The evidence for 17‐keV neutrinos

We have studied the β‐spectrum of 14C using a germanium detector containing a crystal with 14C dissolved in it. We find a feature in the β‐spectrum 17 keV below the endpoint which can be explained by the hypothesis that there is a heavy neutrino emitted in the β‐decay of 14C with a mass of 17.1±0.5 keV and an emission probability of 1.3±0.3%. These results are consistent with observations of similar anomalies in the β‐decays of 3H and 35S, and the internal bremsstrahlung decays of 55Fe and 71Ge.