Neutrino Superbeams and the Magic Baseline

Abstract

We examine the sensitivity to \nu_\mu --> \nu_e of a conceptual neutrino experiment that involves a neutrino superbeam, a Megaton-scale water Cherekov detector, and a "magic" baseline ~7300 km. With realistic beam intensity and exposure time, the mixing parameter sin^2 2\theta_{13} and the sign of "atmospheric" mass-squared difference may be unambiguously probed down to sin^2 22\theta_{13} values below 10^{-3}.