A note on the mixings of heavy neutrinos and muon decays

The authors set limits on the mixing of heavy neutrinos into the muon family /U sub(μi)/sup(2) for neutrino masses in the range of 30 to 70 MeV/c2. Both the Michel parameter and the e+ spectrum are used. This complements limits from leptonic decays of pseudoscalar mesons. They also give indications of how current experiments can be used to improve these limits