Three Twin Neutrinos: Evidence from LSND and MiniBooNE

TL;DR

This paper proposes a model with three twin neutrinos that explains the neutrino appearance excesses observed at LSND and MiniBooNE, fitting the data within a natural theoretical framework involving twin parity and a universal mixing angle.

Contribution

It introduces a twin neutrino model with a universal mixing angle that naturally accounts for experimental anomalies and predicts decay channels consistent with observed data.

Findings

The model fits LSND and MiniBooNE data at around 4σ confidence level.

Heavy twin neutrinos decay into active neutrinos and a Majoron within experimental lengths.

The model explains the larger anti-neutrino excess due to increased scattering cross section.

Abstract

We construct a neutrino model of three twin neutrinos in light of the neutrino appearance excesses at LSND and MiniBooNE. The model, which includes a twin parity, naturally predicts identical lepton Yukawa structures in the Standard Model and the twin sectors. As a result, a universal mixing angle controls all three twin neutrino couplings to the Standard Model charged leptons. This mixing angle is predicted to be the ratio of the electroweak scale over the composite scale of the Higgs boson and has the right order of magnitude to fit the data. The heavy twin neutrinos decay within the experimental lengths into active neutrinos plus a long-lived Majoron and can provide a good fit, at around $4\sigma$ confidence level, to the LSND and MiniBooNE appearance data while simultaneously satisfying the disappearance constraints. For the Majorana neutrino case, the fact that neutrinos have a larger scattering cross section than anti-neutrinos provides a natural explanation to MiniBooNE's observation of a larger anti-neutrino appearance excess.