Explaining the MiniBooNE excess through a mixed model of neutrino oscillation and decay

The electronlike excess observed by the MiniBooNE experiment is explained with a model comprising a new low mass state ($\mathcal{O}(1)\text{ }\text{ }\mathrm{eV}$) participating in neutrino oscillations and a new high mass state ($\mathcal{O}(100)\text{ }\text{ }\mathrm{MeV}$) that decays to $\ensuremath{\nu}+\ensuremath{\gamma}$. Short-baseline oscillation datasets are used to predict the oscillation parameters. Fitting the MiniBooNE energy and scattering angle data, there is a narrow joint allowed region for the decay contribution at 95% CL. The result is a substantial improvement over the single sterile neutrino oscillation model, with $\mathrm{\ensuremath{\Delta}}{\ensuremath{\chi}}^{2}/\mathrm{dof}=19.3/2$ for a decay coupling of $2.8\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}7}\text{ }\text{ }{\mathrm{GeV}}^{\ensuremath{-}1}$, high mass state of 376 MeV, oscillation mixing angle of $7\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$ and mass splitting of $1.3\text{ }\text{ }{\mathrm{eV}}^{2}$. This model predicts that no clear oscillation signature will be observed in the FNAL short baseline program due to the low signal-level.