Neutrino Mass Difference Induced Oscillations in Observed Muon Decays

Abstract

The recent real time KARMEN anomaly for the electron neutrino counting rates (obtained from stopped muon decays) is analyzed by employing a neutrino flavor rotation model in which the muon neutrino is in a superposition of only two mass eigenstates. On the basis of experimental electron neutrino counting oscillations, we find a neutrino mass splitting $|m_2^2-m_1^2|=(0.22\pm 0.02)(eV/c^2)^2$ and a flavor rotation angle $\phi =0.34\pm 0.10$, both within a 95% confidence interval.