On the measurement of leptonic CP violation Original Research Article

We show that the simultaneous determination of the leptonic CP-odd phase δ and the angle θ13 from the subleading transitions νe→νμ and ν̄e→ν̄μ results generically, at fixed neutrino energy and baseline, in two degenerate solutions. In light of this, we refine a previous analysis of the sensitivity to leptonic CP violation at a neutrino factory, in the LMA–MSW scenario, by exploring the full range of δ and θ13. Furthermore, we take into account the expected uncertainties on the solar and atmospheric oscillation parameters and in the average Earth matter density along the neutrino path. An intermediate baseline of O(3000) km is still the best option to tackle CP violation, although a combination of two baselines turns out to be very important in resolving degeneracies.