Test of Lorentz invariance with atmospheric neutrinos

TL;DR

This study used extensive atmospheric neutrino data from Super-Kamiokande to search for Lorentz violation effects, finding no evidence but significantly tightening existing limits on SME coefficients across multiple sectors.

Contribution

It is the first comprehensive search for Lorentz violation in atmospheric neutrinos using the full energy and path length range, setting new stringent limits on SME parameters.

Findings

No evidence of Lorentz violation was observed.

Limits on SME coefficients were improved by up to seven orders of magnitude.

First limits established in the neutrino μτ sector of SME.

Abstract

A search for neutrino oscillations induced by Lorentz violation has been performed using 4,438 live-days of Super-Kamiokande atmospheric neutrino data. The Lorentz violation is included in addition to standard three-flavor oscillations using the non-perturbative Standard Model Extension (SME), allowing the use of the full range of neutrino path lengths, ranging from 15 to 12,800 km, and energies ranging from 100 MeV to more than 100 TeV in the search. No evidence of Lorentz violation was observed, so limits are set on the renormalizable isotropic SME coefficients in the $e\mu$, $\mu\tau$, and $e\tau$ sectors, improving the existing limits by up to seven orders of magnitude and setting limits for the first time in the neutrino $\mu\tau$ sector of the SME.