Discovery potential of T2K and NOvA in the presence of a light sterile neutrino

Abstract: We study the impact of one light sterile neutrino on the prospective data expected to come from the two presently running long-baseline experiments T2K and NOvA when they will accumulate their full planned exposure. Introducing for the first time, the bi-probability representation in the 4-flavor framework, commonly used in the 3-flavor scenario, we present a detailed discussion of the behavior of the vμ → ve and (Formula presented.) transition probabilities in the 3+1 scheme. We also perform a detailed sensitivity study of these two experiments (both in the stand-alone and combined modes) to assess their discovery reach in the presence of a light sterile neutrino. For realistic benchmark values of the mass-mixing parameters (as inferred from the existing global short-baseline fits), we find that the performance of both these experiments in claiming the discovery of the CP-violation induced by the standard CP-phase (Formula presented.) 13 = (Formula presented.) and the neutrino mass hierarchy get substantially deteriorated. The exact loss of sensitivity depends on the value of the unknown CP-phase (Formula presented.) 14. Finally, we estimate the discovery potential of total CP-violation (i.e., induced simultaneously by the two CP-phases (Formula presented.) 13 and (Formula presented.) 14), and the capability of the two experiments of reconstructing the true values of such CP-phases. The typical (1 (Formula presented.) level) uncertainties on the reconstructed phases are approximately 400 for (Formula presented.) 13 and 500 for (Formula presented.) 14.