On The Decaying-Sterile Neutrino Solution to the Electron (Anti)Neutrino Appearance Anomalies

TL;DR

This paper investigates a decaying sterile neutrino model to explain anomalies in LSND and MiniBooNE data, proposing a heavy neutrino that mixes with muon neutrinos and decays into electron neutrinos and a light scalar, fitting the data well.

Contribution

It introduces a decaying sterile neutrino hypothesis that can account for the anomalies and evade existing constraints, with testable predictions for future experiments.

Findings

The decaying-sterile-neutrino model fits LSND and MiniBooNE data.

The model evades constraints from disappearance searches.

Future SBN experiments can test this hypothesis.

Abstract

We explore the hypothesis that the unexplained data from LSND and MiniBooNE are evidence for a new, heavy neutrino mass-eigenstate that mixes with the muon-type neutrino and decays into an electron-type neutrino and a new, very light scalar particle. We consider two different decay scenarios, one with Majorana neutrinos, one with Dirac neutrinos; both fit the data equally well. We find a reasonable, albeit not excellent, fit to the data of MiniBooNE and LSND. The decaying-sterile-neutrino hypothesis, however, cleanly evades constraints from disappearance searches and precision measurements of leptonic meson decays, as long as $1~{\rm MeV}\gtrsim m_4\gtrsim 10$~keV. The SBN program at Fermilab should be able to definitively test the decaying-sterile-neutrino hypothesis.