Optimization of the baseline and the parent muon energy for a low energy neutrino factory

Abstract

We discuss the optimal setup for a low energy neutrino factory in order to achieve a 5σ-discovery of a nonzero mixing angle θ_{13}, a nonzero CP phase δ_{CP}, and the mass hierarchy. We explore parent muon energies in the range 5--16 GeV, and baselines in the range 500--5000 km. We present the results in terms of the reach in sin^2θ_{13}, emphasizing the dependence of the optimal baseline on the true value of δ_{CP}. We show that the sensitivity of a given setup typically increases with parent muon energy, reaching saturation for higher energies. The saturation energy is larger for longer baselines; we present an estimate of this dependence. In the light of the recent indications of a large θ_{13}, we also determine how these preferences would change if indeed a large θ_{13} is confirmed. In such a case, the baselines ~2500 km (~1500 km) may be expected to lead to hierarchy determination (δ_{CP} discovery) with the minimum exposure.

16 pages, 8 figures. Matches published version