First hint for CP violation in neutrino oscillations from upcoming superbeam and reactor experiments

Abstract

We compare the physics potential of the upcoming neutrino oscillation experiments Daya Bay, Double Chooz, NOνA, RENO, and T2K based on their anticipated nominal luminosities and schedules. After discussing the sensitivity to θ13 and the leading atmospheric parameters, we demonstrate that leptonic CP violation will hardly be measurable without upgrades of the T2K and NOνA proton drivers, even if θ13 is large. In the presence of the proton drivers, the fast track to hints for CP violation requires communication between the T2K and NOνA collaborations in terms of a mutual synchronization of their neutrino-antineutrino run plans. Even in that case, upgrades will only discover CP violation in a relatively small part of the parameter space at the 3σ confidence level, while 90% confidence level hints will most likely be obtained. Therefore, we conclude that a new facility will be required if the goal is to obtain a significant result with high probability.