Multi-ring signatures of the oscillation $\nu_\mu \rightarrow \nu_e$ in a water Cherenkov detector

Abstract.

Multi-ring signatures of $\nu_e$ appearance via the oscillation $\nu_\mu \rightarrow \nu_e$ are formulated for a water Cherenkov detector. These signatures are appropriate for long-baseline neutrino experiments operating at relatively high neutrino energies $E_\nu > 2$ GeV that emphasize the matter effect. The NC background is less for selected multi-ring events than for 1e-like events, and may be directly estimated from the data. Our results suggest that best sensitivity to $\sin^2 2\theta_{13}$ and to the sign of $\Delta m^2_{31}$ can be reached with baselines over some 6000 km.