Magical properties of a 2540 km baseline superbeam experiment

Abstract

Lack of any information on the CP violating phase δCP weakens our ability to determine neutrino mass hierarchy. Magic baseline of 7500 km was proposed to overcome this problem. However, to obtain large enough fluxes, at this very long baseline, one needs new techniques of generating high intensity neutrino beams. In this Letter, we highlight the magical properties of a 2540 km baseline. At such a baseline, using a narrow band neutrino superbeam whose no oscillation event rate peaks around the energy 3.5 GeV, we can determine neutrino mass hierarchy independently of the CP phase. For sin22θ13⩾0.05, a very modest exposure of 10 Kiloton-years is sufficient to determine the hierarchy. For 0.02⩽sin22θ13⩽0.05, an exposure of about 100 Kiloton-years is needed.