T-violation tests for relativity principles

Abstract

We consider the implications of a violation of the equivalence principle or of Lorentz invariance in the neutrino sector for the T-asymmetry $ΔP_T \equiv P(ν_α \to ν_β) - P(ν_β \to ν_α)$ in a three-flavour framework. We find that additional mixing due to these mechanisms, while obeying all present bounds, can lead to a substantial enhancement, suppression, and/or sign change in $ΔP_T$ for the preferred energies and baselines of a neutrino factory. This in turn allows for the possibility of improving existing constraints by several orders of magnitude.