Search for a Lorentz invariance violation contribution in atmospheric neutrino oscillations using MACRO data

TL;DR

This study uses MACRO atmospheric neutrino data to test for Lorentz invariance violations, setting stringent limits that support standard neutrino oscillation models and constrain exotic physics.

Contribution

The paper provides the first limits on Lorentz invariance violation parameters using atmospheric neutrino oscillation data from MACRO.

Findings

Limits on Lorentz violation parameter |Delta v| < 6 x 10^(-24) at sin^2θ_v=0

Limits on |Delta v| < 2.5--5 x 10^(-26) at sin^2θ_v=±1

Data disfavor exotic Lorentz violation effects at a sub-dominant level

Abstract

Neutrino-induced upward-going muons in MACRO have been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of nu_mu -> nu_tau transitions. The data disfavor these exotic possibilities even at a sub-dominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Delta v| < 6 * 10^(-24) at sin2theta_v = 0 and |Delta v| < 2.5--5 * 10^(-26) at sin2theta_v = +/-1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the Equivalence Principle.