Tests of Lorentz violation in muon antineutrino to electron antineutrino oscillations

TL;DR

This paper tests for Lorentz and CPT violation in muon antineutrino to electron antineutrino oscillations using LSND data, finding no sidereal variation but setting bounds on SME coefficients, and suggesting future tests with other experiments.

Contribution

It applies a new SME formalism to analyze LSND data for Lorentz and CPT violation, providing bounds on SME coefficients and proposing further experimental tests.

Findings

LSND data shows no sidereal variation in neutrino oscillations.

Bounds on SME coefficients are of order 10^{-19} GeV.

Potential for testing Lorentz violation with other short baseline experiments.

Abstract

A recently developed Standard-Model Extension (SME) formalism for neutrino oscillations that includes Lorentz and CPT violation is used to analyze the sidereal time variation of the neutrino event excess measured by the Liquid Scintillator Neutrino Detector (LSND) experiment. The LSND experiment, performed at Los Alamos National Laboratory, observed an excess, consistent with neutrino oscillations, of ${\bar\nu}_e$ in a beam of ${\bar\nu}_\mu$. It is determined that the LSND oscillation signal is consistent with no sidereal variation. However, there are several combinations of SME coefficients that describe the LSND data; both with and without sidereal variations. The scale of Lorentz and CPT violation extracted from the LSND data is of order $10^{-19}$ GeV for the SME coefficients $a_L$ and $E \times c_L$. This solution for Lorentz and CPT violating neutrino oscillations may be tested by other short baseline neutrino oscillation experiments, such as the MiniBooNE experiment.