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

The energy spectrum of neutrino-induced upward-going muons in MACRO has been analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant source of νμ→ντ transitions. The data disfavor these exotic possibilities even at a subdominant level, and stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter |Δv|<6×10−24 at sin2θv=0 and |Δv|<2.5-5×10−26 at sin2θv=±1. These limits can also be re-interpreted as upper bounds on the parameters describing violation of the equivalence principle.