Getting the best out of T2K and NOvA

TL;DR

This paper analyzes how combined data from T2K and NOvA can determine neutrino mass hierarchy and CP violation, emphasizing the importance of increased statistics and the interplay between hierarchy and deltaCP measurements.

Contribution

It demonstrates the conditions under which T2K and NOvA can determine neutrino hierarchy and CP violation, highlighting the impact of increased data collection.

Findings

Hierarchy can be identified with current plans for certain deltaCP ranges.

Increasing NOvA and T2K statistics improves hierarchy and deltaCP measurement.

Shorter baseline experiments do not significantly enhance results.

Abstract

We explore the combined physics potential of T2K and NOvA in light of the moderately large measured value of theta13. For sin^2 2*theta13 = 0.1, which is close to the best fit value, a 90% C.L. evidence for the hierarchy can be obtained only for the combinations (Normal hierarchy, -170 <= deltaCP <= 0) and (Inverted hierarchy, 0 <= deltaCP <= 170), with the currently planned runs of NOvA and T2K. However, the hierarchy can essentially be determined for any value of deltaCP, if the statistics of NOvA are increased by 50% and those of T2K are doubled. Such an increase will also give an allowed region of deltaCP around its true value, except for the CP conserving cases deltaCP = 0 or 180. We demonstrate that any measurement of deltaCP is not possible without first determining hierarchy. We find that comparable data from a shorter baseline (L ~ 130 km) experiment will not lead to any significant improvement.