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

TL;DR

Upcoming neutrino experiments have limited potential to detect CP violation without upgrades, requiring collaboration and new facilities for significant results in neutrino physics.

Contribution

This paper compares the sensitivity of upcoming experiments and highlights the need for upgrades and collaboration to detect leptonic CP violation.

Findings

CP violation detection is unlikely without upgrades

Collaboration between T2K and NOvA is crucial

New facilities are needed for significant CP violation discovery

Abstract

We compare the physics potential of the upcoming neutrino oscillation experiments Daya Bay, Double Chooz, NOvA, RENO, and T2K based on their anticipated nominal luminosities and schedules. After discussing the sensitivity to theta_{13} and the leading atmospheric parameters, we demonstrate that leptonic CP violation will hardly be measurable without upgrades of the T2K and NOvA proton drivers, even if theta_{13} is large. In the presence of the proton drivers, the fast track to hints for CP violation requires communication between the T2K and NOvA 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 3 sigma 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.