POSSIBLE VIOLATION OF THE EQUIVALENCE PRINCIPLE BY NEUTRINOS

We consider the effect of a long-range, flavor-changing tensor interac tion of possible gravitational origin. Neutrino-mixing experiments pro vide the most sensitive probe to date for such forces-testing the equi valence principle at levels below 10(-20). Here we justify and general ize a formalism for describing such effects. The constraints from neut rino-mixing experiments on gravitationally induced mixing are calculat ed. Our detailed analysis of the atmospheric neutrino data confirms a remarkable result: the atmospheric neutrino data imply the same size v iolation of the equivalence principle as do the solar neutrino data. A dditional tests of this suggestive result are discussed.