Heavy Sterile Neutrinos in Tau Decays and the MiniBooNE Anomaly

TL;DR

This paper explores the role of a heavy sterile neutrino with a large magnetic moment in tau decays, proposing that analyzing certain decay channels with displaced vertices can test its existence as an explanation for the MiniBooNE anomaly.

Contribution

It introduces a novel sterile neutrino model involving decay signatures in tau decays, providing a new experimental test for the MiniBooNE anomaly beyond oscillation explanations.

Findings

Displaced vertex signatures in tau decays can indicate sterile neutrino presence.

Existing data can be used to search for these decay signatures.

The proposed sterile neutrino could explain MiniBooNE excess events.

Abstract

Current results of the MiniBooNE experiment show excess events that indicate neutrino oscillations, but only if one goes beyond the standard 3 family scenario. Recently a different explanation of the events has been given, not in terms of oscillations but by the production and decay of a massive sterile neutrino with large transition magnetic moment. We study the effect of such a sterile neutrino in the rare decays $\tau^- \rightarrow \mu^- \mu^+ \pi^- \nu$ and $\tau^{-}\rightarrow \mu^{-} \mu^{+} e^{-} \nu \nu$. We find that searches for these decays featuring displaced vertices between the $\mu^-$ and the other charged particles, constitute good tests for the existence of the sterile neutrino proposed to explain the MiniBooNE anomaly. These searches could be done with already existing experimental data.