Explaining the MiniBooNE excess by a decaying sterile neutrino with mass in the 250 MeV range

TL;DR

This paper proposes that the MiniBooNE excess of electron-like events can be explained by a 250 MeV sterile neutrino decaying into a photon and a light neutrino, with specific production mechanisms and testable predictions.

Contribution

It introduces a sterile neutrino decay model to explain MiniBooNE excess, linking it to kaon decays and suggesting experimental tests in current neutrino detectors.

Findings

Model can account for the observed excess.

Predictions include specific event time distributions.

Suggests new search strategies in neutrino experiments.

Abstract

The MiniBooNE collaboration has reported an excess of $460.5\pm 95.8$ electron-like events ($4.8\sigma$). We propose an explanation of these events in terms of a sterile neutrino decaying into a photon and a light neutrino. The sterile neutrino has a mass around 250 MeV and it is produced from kaon decays in the proton beam target via mixing with the muon or the electron in the range $10^{-11} \lesssim |U_{\ell 4}|^2 \lesssim 10^{-7}$ ($\ell = e,\mu$). The model can be tested by considering the time distribution of the events in MiniBooNE and by looking for single-photon events in running or upcoming neutrino experiments, in particular by the suite of liquid argon detectors in the short-baseline neutrino program at Fermilab.