${\nu }_{\mu }$ disappearance at the SPL, T2K-I, NO$\nu$A and the Neutrino Factory

Abstract

We study the measurement of the atmospheric neutrino oscillation parameters, ${\theta }_{23}$ and $\Delta m_{23}^2$, at the ${\nu }_{\mu }$ disappearance channel at three conventional beam facilities, the SPL, T2K-phase I and NO$\nu$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, ${\theta }_{13}$ and the leptonic CP-violating phase $\delta$. In our analyis, the effect of the two discrete ambiguities, $\mathrm{sign}(\Delta m_{23}^2)$ and $\mathrm{sign}(\tan 2{\theta }_{23})$, is explicitly taken into account. We analyse also the ${\nu }_{\mu }$ disappearance channel at the Neutrino Factory, and combine it with the ``golden'' ${\nu }_e\to {\nu }_{\mu }$ and ``silver'' ${\nu }_e\to {\nu }_{\tau }$ appearance channels to study its impact on the measurement of ${\theta }_{13}$ and $\delta$. Eventually, we present the sensitivity of the four facilities to different observables: ${\theta }_{13}$, $\delta$, maximal ${\theta }_{23}$, the sign of the atmospheric mass difference, $s_{atm}$, and the ${\theta }_{23}$-octant, $s_{oct}$.

Comments: 40 pages using epsfig; bibliography modified