New method for an improved antineutrino energy reconstruction with charged-current interactions in next-generation detectors

We propose and validate a method of antineutrino energy reconstruction for charged-current meson-less interactions on composite fully active targets containing hydrogen (such as hydrocarbon scintillator), which is largely free of the poorly understood nuclear effects that usually distort and bias attempts to measure neutrino energy. The method is based on the precise event-by-event measurement of the outgoing neutron kinetic energy and the subsequent assessment of the momentum imbalance on the plane transverse to the incoming antineutrino direction. For an antineutrino flux peaked at around 600 MeV measured using a finely grained 2 x 2 x 2 m(3) three-dimensional scintillator tracker, the neutrino energy resolution is expected to be around 7%, compared to the 15% expected using traditional neutrino energy reconstruction techniques. Analogous results can be obtained for other detectors with similar characteristics.