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, $\Delta P_T\equiv P({\nu }_{\alpha }\to {\nu }_{\beta })-P({\nu }_{\beta }\to {\nu }_{\alpha })$, 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 $\Delta P_T$ 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 $({\nu }_e,{\nu }_{\mu })$ and $({\nu }_e,{\nu }_{\tau })$ sectors.

Comments: RevTeX4, 10 pages, 11 figures; To appear in PRD; v2: two references added