Search for exotic contributions to atmospheric neutrino oscillations

Abstract

The energy spectrum of neutrino-induced upward-going muons in MACRO was analysed in terms of relativity principles violating effects, keeping standard mass-induced atmospheric neutrino oscillations as the dominant effect. The data disfavor these possibilities even at a sub-dominant level; stringent 90% C.L. limits are placed on the Lorentz invariance violation parameter $|\hat{I}”v|<6\times 10^{-24}$ at $\sin 2\hat{I}{¸}_v$ = 0 and $|\hat{I}”v|<2.5\tilde{A}\cdot 5\times 10^{-26}$ at $\sin 2\hat{I}{¸}_v$ = $\pm$1. The limits can be re-interpreted as bounds on the Equivalence Principle violation parameters.

Presented at the 29th I.C.R.C., Pune, India (2005)