$ν_μ$ disappearance at the SPL, T2K-I, NO$ν$A and the Neutrino Factory

Abstract

We study the measurement of the atmospheric neutrino oscillation parameters, $θ_{23}$ and $Δm^2_{23}$, at the $ν_μ$ disappearance channel at three conventional beam facilities, the SPL, T2K-phase I and NO$ν$A. These two parameters have been shown to be of crucial importance in the measurement of two of the unknowns of the PMNS mixing matrix, $θ_{13}$ and the leptonic CP-violating phase $δ$. In our analyis, the effect of the two discrete ambiguities, ${\rm sign}(Δm^2_{23})$ and ${\rm sign}(\tan 2 θ_{23})$, is explicitly taken into account. We analyse also the $ν_μ$ disappearance channel at the Neutrino Factory, and combine it with the ``golden'' $ν_e \to ν_μ$ and ``silver'' $ν_e \to ν_τ$ appearance channels to study its impact on the measurement of $θ_{13}$ and $δ$. Eventually, we present the sensitivity of the four facilities to different observables: $θ_{13}$, $δ$, maximal $θ_{23}$, the sign of the atmospheric mass difference, $s_{atm}$, and the $θ_{23}$-octant, $s_{oct}$.