Lorentz noninvariant neutrino oscillations without neutrino mass

TL;DR

This paper evaluates various Lorentz noninvariant models for massless neutrino oscillations, finding none can simultaneously explain atmospheric, solar, and KamLAND neutrino data.

Contribution

It systematically analyzes all nineteen Lorentz noninvariant structures within the Standard Model Extension for neutrino oscillations without mass, identifying their limitations.

Findings

Models predict maximal mixing and 1/E dependence for atmospheric neutrinos.

None of the models can fit solar and KamLAND data simultaneously.

Direction-independent models are considered due to lack of evidence for direction dependence.

Abstract

The bicycle model of Lorentz noninvariant neutrino oscillations without neutrino masses naturally predicts maximal mixing and a 1/E dependence of the oscillation argument for $\nu_\mu \to \nu_\tau$ oscillations of atmospheric and long-baseline neutrinos, but cannot also simultaneously fit the data for solar neutrinos and KamLAND. We examine all nineteen possible structures of the Standard Model Extension for Lorentz noninvariant oscillations of massless neutrinos that naturally have a 1/E dependence at high neutrino energy. Due to the lack of any evidence for direction dependence, we consider only direction-independent oscillations. Although we find a number of models with a 1/E dependence for atmospheric and long-baseline neutrinos, none can also simultaneously fit solar and KamLAND data.