A low energy neutrino factory for large $\theta_{13}$

If the value of $\theta_{13}$ is within the reach of the upcoming generation of long-baseline experiments, T2K and NO$\nu$A, we show that a low-energy neutrino factory, with peak energy in the few GeV range, would provide a sensitive tool to explore CP-violation and the neutrino mass hierarchy. We consider baselines with typical length 1000--1500 km. The unique performance of the low energy neutrino factory is due to the rich neutrino oscillation pattern at energies between 1 and 4 GeV at baselines $\mathcal{O}(1000)$ km. We perform both a semi-analytical study of the sensitivities and a numerical analysis to explore how well this setup can measure $\theta_{13}$, CP-violation, and determine the type of mass hierarchy and the $\theta_{23}$ quadrant. A low energy neutrino factory provides a powerful tool to resolve ambiguities and make precise parameter determinations, for both large and fairly small values of the mixing parameter $\theta_{13}$.