Neutrino oscillation physics potential of the T2K experiment

ioannis akkizidis, sunil kumar khandelwal;

The observation of the recent electron neutrino appearance in a muon neutrino beam and the high-precision measurement of the mixing angle θ13 have led to a re-evaluation of the physics potential of the T2K long-baseline neutrino oscillation experiment. Sensitivities are explored for CP violation in neutrinos, non-maximal sin2 2θ23, the octant of θ23, and the mass hierarchy, in addition to the measurements of δCP, sin2 θ23, and m2 32, for various combinations of ν-mode and ¯ν -mode data-taking. With an exposure of 7.8 × 1021 protons-on-target, T2K can achieve 1 σ resolution of 0.050 (0.054) on sin2 θ23 and 0.040 (0.045) × 10−3 eV2 on m2 32 for 100% (50%) neutrino beam mode running assuming sin2 θ23 = 0.5 and m2 32 = 2.4 × 10−3 eV2. T2K will have sensitivity to the CP-violating phase δCP at 90% C.L. or better over a significant range. For example, if sin2 2θ23 is maximal (i.e. θ23 = 45◦) the range is −115◦ < δCP < −60◦ for normal hierarchy and +50◦ < δCP < +130◦ for inverted hierarchy. When T2K data is combined with data from the NOνA experiment, the region of oscillation parameter space where there is sensitivity to observe
a non-zero δCP is substantially increased compared to if each experiment is analyzed alone.