Energy reconstruction in quasi-elastic events unfolding physics and detector effects

In this paper, we study the use of spectral information in the measurement of neutrino oscillation parameters for a neutrino Super Beam. At low energies, neutrino interactions are dominated by quasi-elastic processes, where the final state is solely composed of a lepton and a proton. In water detectors the proton is below Cherenkov threshold and the only visible particle is the lepton; using the knowledge of the beam direction, it is still possible to reconstruct the neutrino energy using simple kinematics. At low energy this reconstruction is heavily affected by nuclear physics effects and detector resolution. We show that it is possible to unfold such effects using a Monte Carlo reweighting technique, obtaining substantial improvements to the measurements of oscillation parameters.