What can we learn about the lepton CP phase in the next 10 years?

We discuss how the lepton CP phase can be constrained by accelerator and reactor measurements in an era without dedicated experiments for CP violation search. To characterize globally the sensitivity to the CP phase delta_{CP}, we introduce a new measure, the CP exclusion fraction, which quantifies what fraction of the delta_{CP} space can be excluded at a given input values of theta_{23} and delta_{CP}. Using the measure we study the CP sensitivity which may be possessed by the accelerator experiments T2K and NOvA. We show that, if the mass hierarchy is known, T2K and NOvA alone may exclude, respectively, about 50%-60% and 40%-50% of the delta_{CP} space at 90% CL by 10 years running, provided that a considerable fraction of beam time is devoted to the antineutrino run. The synergy between T2K and NOvA is remarkable, leading to the determination of the mass hierarchy through CP sensitivity at the same CL.

Combining Accelerator and Reactor Measurements of theta_13; The First Result

The lepton mixing angle theta_13, the only unknown angle in the standard three-flavor neutrino mixing scheme, is finally measured by the recent reactor and accelerator neutrino experiments. We perform a combined analysis of the data coming from T2K, MINOS, Double Chooz, Daya Bay and RENO experiments and find sin^2 2theta_13 = 0.096 pm 0.013 (pm 0.040) at 1 sigma (3 sigma) CL and that the hypothesis theta_13 = 0 is now rejected at a significance level of 7.7 sigma. We also discuss the near future expectation on the precision of the theta_13 determination by using expected data from these ongoing experiments.

Large Extra Dimensions and Neutrino Oscillations

We consider a model where right-handed neutrinos propagate in a large compactified extra dimension, engendering Kaluza-Klein (KK) modes, while the standard model particles are restricted to the usual 4-dimensional brane. A mass term mixes the KK modes with the standard left-handed neutrinos, opening the possibility of change the 3 generation mixing pattern. We derive bounds on the maximum size of the extra dimension from neutrino oscillation experiments. We show that this model provides a possible explanation for the deficit of nu_e in Ga solar neutrino calibration experiments and of the anti-nu_e in short baseline reactor experiments.