A low energy neutrino factory with non-magnetic detectors

We show that a very precise neutrino/anti-neutrino event separation is not mandatory to cover the physics program of a low energy neutrino factory and thus non-magnetized detectors like water Cerenkov or liquid Argon detectors can be used. We point out, that oscillation itself strongly enhances the signal to noise ratio of a wrong sign muon search, provided there is sufficiently accurate neutrino energy reconstruction. Further. we argue that apart from a magnetic field, other means to distinguish neutrino from anti-neutrino events (at least statistically) can be explored. Combined with the fact that nonmagnetic detectors potentially can be made very big, we show that modest neutrino/anti-neutrino separations at the level of 50% to 90% are sufficient to obtain good sensitivity to CP violation and the neutrino mass hierarchy for sin(2) 2 theta(13) > 10(-3). These non-magnetized detectors have a rich physics program outside the context of a neutrino factory. including topics like supernova neutrinos and proton decay. Hence, our observation opens the possibility to use a multi-purpose detector also in a neutrino factory beam. (C) 2008 Elsevier B.V. All rights reserved.