Superbeams plus neutrino factory: the golden path to leptonic CP violation Original Research Article

Superbeams (SB) and neutrino factories (NF) are not alternative facilities for exploring neutrino oscillation physics, but successive steps. The correct strategy is to contemplate the combination of their expected physics results. We show its important potential on the disappearance of fake degenerate solutions in the simultaneous measurement of θ13 and leptonic CP violation. Intrinsic, sign(Δm132) and θ23 degeneracies are shown to be extensively eliminated when the results from one NF baseline and a SB facility are combined. A key point is the different average neutrino energy and baseline of the facilities. For values of θ13 near its present limit, the short NF baseline, e.g., L=732 km, becomes, after such a combination, a very interesting distance. For smaller θ13, an intermediate NF baseline of O(3000 km) is still required.