Understanding the performance of the low energy neutrino factory: the dependence on baseline distance and stored-muon energy

Abstract

Motivated by recent hints of large θ13 from the T2K, MINOS and Double Chooz experiments, we study the physics reach of a Low Energy Neutrino Factory (LENF) and its dependence on the chosen baseline distance, L, and stored-muon energy, E_μ, in order to ascertain the configuration of the optimal LENF. In particular, we study the performance of the LENF over a range of baseline distances from 1000 km to 4000 km and stored-muon energies from 4 GeV to 25 GeV, connecting the early studies of the LENF (1300 km, 4.5 GeV) to those of the conventional, high-energy neutrino factory design (4000 km and 7000 km, 25 GeV). Three different magnetized detector options are considered: a Totally-Active Scintillator Detector (TASD) and two models of a liquid-argon detector distinguished by optimistic and conservative performance estimates. In order to compare the sensitivity of each set-up, we compute the full δ-dependent discovery contours for the determination of non-zero θ13, CP-violating values of δ and the mass hierarchy. In the case of large θ13 with sin^2(2*θ13) = (few)*10^{-3}, the LENF provides a strong discovery potential over the majority of the L-E_μ parameter space and is a promising candidate for the future generation of long baseline experiments aimed at discovering CP-violation and the mass hierarchy, and at making a precise determination of the oscillation parameters.