Radiative decay of heavy neutrinos at MiniBooNE and MicroBooNE

Abstract

The MiniBooNE experiment reported results from the analysis of ${\nu }_e$ and ${\overline{\nu }}_e$ appearance searches, which showed an excess of signal-like events at low reconstructed neutrino energies with respect to the expected background. A proposed explanation for this anomaly is based on the existence of a heavy ($\sim 50$~MeV) sterile neutrino. These ${\nu }_h$ would be produced by ${\nu }_{\mu }$ electromagnetic and neutral current interactions. A fraction of them decays radiatively inside the detector. The emitted photon is misidentified as an electron or positron in MiniBooNE. We have investigated the ${\nu }_h$ production by coherent and incoherent electroweak interactions at the MiniBooNE and MicroBooNE targets, CH${}_2$ and Ar, respectively. Studying the ${\nu }_h$ propagation inside the detector, we obtain the energy and angular distributions of emitted photons for a choice of model parameters. The distinctive shape and total number of photon events from this mechanism at MicroBooNE makes its experimental investigation possible.

Comments: Poster presented at NuPhys2016 (London, 12-14 December 2016). 4 pages, LaTeX, 8 eps