Can the hint of δCP from T2K also indicate the hierarchy and octant?

Abstract

The T2K neutrino data has already given a hint for the best-fit value of the leptonic CP phase δCP as −90◦. In this paper we ask the question that if this hint is confirmed by the subsequent neutrino and anti-neutrino runs of T2K, then can it also give any information about the other two remaining unknown oscillation parameters—the neutrino mass hierarchy and octant of θ23. We find that if T2K runs in only neutrino mode with its full targeted exposure, then δCP = −90◦ would indicate the true hierarchy as normal and the true octant as higher. On the other hand if T2K runs in equal neutrino and anti-neutrino mode then the true hierarchy can be confirmed as normal but the octant will remain undetermined. We have also studied the effect of anti-neutrino runs on CP sensitivity of T2K.