Light sterile neutrinos and their implications on currently running long-baseline and neutrinoless double-beta decay experiments

Abstract

Recent νe appearance data from the Mini Booster Neutrino Experiment support the excess of events reported by the Liquid Scintillator Neutrino Detector, which provides an indirect hint of the existence of eV-scale sterile neutrinos. As these sterile neutrinos can mix with the standard active neutrinos, in this paper we explore the effect of such active–sterile mixing on the determination of various oscillation parameters by the currently running long-baseline neutrino experiments T2K and NOνA. We find that the existence of sterile neutrinos can lead to new kinds of degeneracies among these parameters which would substantially deteriorate the mass hierarchy sensitivity of the NOνA experiment. We further notice that the inclusion of data from the T2K experiment helps in resolving the degeneracies. The impact of new CP-violating phases δ14 and δ34 on the maximal CP violation exclusion sensitivity for the NOνA experiment has also been illustrated. Finally, we discuss the implication of such light sterile neutrinos on neutrinoless double-beta decay processes in line with recent experimental results, as well as on the sensitivity reach of future experiments.