Appearance and disappearance signals at a β-beam and a super-beam facility

In this Letter we present the study of the eightfold degeneracy in the (θ13,δ) measurement including both appearance and disappearance channels. We analyse, for definiteness, the case of a standard low-γ β-beam and a 4 MW SPL super-beam facility, both aiming at a UNO-like Mton water Čerenkov detector located at the Fréjus laboratory, L=130 km. In the β-beam case, the νe disappearance channel does not improve the (θ13,δ) measurement when a realistic (i.e., ⩾2%) systematic error is included. In the super-beam case, the νμ disappearance channel could, instead, be quite useful in reducing the impact of the eightfold degeneracy in the (θ13,δ) measurement, especially once the error on the atmospheric mass difference is fully taken into account in the fit.