Why care about $(\theta_{13},\delta)$ degeneracy at future neutrino experiments

Abstract

The presence of several clone solutions in the simultaneous measurement of ($\theta_{13},\delta$) has been widely discussed in literature. Here, after a pedagogical introduction on why these clones arise, we discuss how the clones location in the ($\theta_{13},\delta$) plane change as a function of the physical input pair ($\bar\theta_{13},\bar\delta$). We compare the clone flow of a set of possible future neutrino experiments: the CERN SuperBeam, BetaBeam and Neutrino Factory proposals. We show that the combination of these specific BetaBeam and SuperBeam could not help in solving the degeneracies. The combination of one of them with the Neutrino Factory Golden and Silver channel can, instead, be used to solve completely the eightfold degeneracy.