Sensitivity of medium-baseline reactor neutrino mass-hierarchy experiments to nonstandard interactions

Abstract

We explore the impact of nonstandard interactions at source and detector on the interpretation of reactor electron neutrino disappearance experiments with short- and medium-baseline designs. We use the constraints from the recent results from short-baseline experiments and generalize current estimates of medium-baseline event rates to include charged current interactions at source and detector with standard Lorentz structure but with nonstandard flavor structure. We find that the average spectrum of observed events at a baseline of 50 km, in the middle of the currently favored region, provides a probe of new interactions. We show that an improvement in sensitivity to nonstandard interactions is possible if combined with improved precision of input mixing parameters in independent experiments, despite ambiguity in interpretation of medium-baseline data. We show that nonstandard interactions can enhance or suppress the sensitivity of experiments to the mass hierarchy, depending on the phases of the parameters and the CP-violating phase in the standard three-neutrino mixing picture.