Experimental constraints on a minimal and nonminimal violation of the equivalence principle in the oscillations of massive neutrinos.

Abstract

The negative results of the oscillations experiments are discussed with thehypothesis that the various neutrino types are not universally coupled togravity. In this case the transition probabiltiy between two different flavoreigenstates may be affected by the local gravitational field present in aterrestrial laboratory, and the contribution of gravity can interfere, ingeneral, with the mass contribution to the oscillation process. In particularit is shown that even a strong violation of the equivalence principle could becompatible with the experimental data, provided the gravity-induced energysplitting is balanced by a suitable neutrino mass difference.