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MiniBooNE Anomaly and Heavy Neutrino Decay

2009; American Physical Society; Volume: 103; Issue: 24 Linguagem: Inglês

10.1103/physrevlett.103.241802

1092-0145

S. Gninenko,

Astrophysics and Cosmic Phenomena

The anomaly in the low-energy distribution of quasielastic neutrino events reported by the MiniBooNE Collaboration is discussed. We show that the observed excess of electronlike events could originate from the production and decay of a heavy neutrino (${\ensuremath{\nu}}_{h}$) in the MiniBooNE detector. The ${\ensuremath{\nu}}_{h}$ with the mass around 500 MeV is created by mixing in ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ neutral-current interactions and decays radiatively into $\ensuremath{\nu}\ensuremath{\gamma}$ with the lifetime ${\ensuremath{\tau}}_{{\ensuremath{\nu}}_{h}}\ensuremath{\lesssim}{10}^{\ensuremath{-}9}$ s due to a transition magnetic moment between the ${\ensuremath{\nu}}_{h}$ and a light neutrino $\ensuremath{\nu}$. Existing experimental data are found to be consistent with a mixing strength between the ${\ensuremath{\nu}}_{h}$ and the ${\ensuremath{\nu}}_{\ensuremath{\mu}}$ of $|{U}_{\ensuremath{\mu}h}{|}^{2}\ensuremath{\simeq}(1\ensuremath{-}4)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ and a ${\ensuremath{\nu}}_{h}$ transition magnetic moment of ${\ensuremath{\mu}}_{\mathrm{tr}}\ensuremath{\simeq}(1\ensuremath{-}6)\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}9}{\ensuremath{\mu}}_{B}$. Finally, we discuss the reason why no significant excess of low-energy events has been observed in the recent antineutrino data.