Is large lepton mixing excluded?
Is large lepton mixing excluded?
The original ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}\ensuremath{-}(or{\overline{\ensuremath{\nu}}}_{\ensuremath{\tau}}\ensuremath{-})$ energy spectrum from the gravitational collapse of a star has a larger average energy than the spectrum for ${\overline{\ensuremath{\nu}}}_{e}$ since the opacity of ${\overline{\ensuremath{\nu}}}_{e}$ exceeds that of ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}(or{\ensuremath{\nu}}_{\ensuremath{\tau}})$. Flavor neutrino conversion ${\overline{\ensuremath{\nu}}}_{e}\ensuremath{\leftrightarrow}{\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ induced by lepton mixing results in partial permutation of the original ${\overline{\ensuremath{\nu}}}_{e}$ and ${\overline{\ensuremath{\nu}}}_{\ensuremath{\mu}}$ spectra. …