T-violation in flavour oscillations as a test for relativity principles at a neutrino factory

Abstract

We study the effects of violation of the equivalence principle (VEP) or violation of Lorentz invariance (LIV) in the neutrino sector on the asymmetry between T-conjugate oscillation probabilities, $ΔP_T \equiv P(ν_α \to ν_β) - P(ν_β \to ν_α)$, in a three-flavour framework. We find that additional mixing due to these mechanisms, while obeying all present bounds, can lead to an observable enhancement, suppression, and/or sign change in $ΔP_T$ for the preferred energies and baselines of a neutrino factory. The measurement of this asymmetry can be used to establish a new upper limit of order $10^{-26}$ on VEP or LIV in the $(ν_e, ν_μ)$ and $(ν_e, ν_τ)$ sectors.