Explaining the MiniBooNE excess through a mixed model of neutrino oscillation and decay
S. Vergani, N. Kamp, A. Diaz, C. Argüelles, J. M. Conrad, M. H. Shaevitz, M. A. Uchida
Abstract
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.