Longitudinal kinematic imbalances in (anti-)neutrino interactions for
improved measurements of nuclear removal energies and the axial vector form
factor
Current and future accelerator neutrino oscillation experiments require an
improved understanding of nuclear effects in neutrino-nucleus interactions. One
important systematic uncertainty is given by potential mismodeling of the
removal energy, which biases the reconstruction of the neutrino energy. In this
manuscript, we introduce a novel observable for accelerator neutrino
oscillation experiments, the visible longitudinal momentum imbalance,
reconstructed in charged current quasi-elastic interactions from the outgoing
charged lepton and nucleon. Minimally dependent on the neutrino energy and
directly sensitive to the removal energy distribution, we demonstrate a method
to constrain the latter. Further, we show how the use of the longitudinal
imbalance in anti-neutrino interactions in a target containing hydrogen allows
for an improved, high-purity selection of the interactions on hydrogen. This
approach offers the potential for precise measurements of the nuclear axial
vector form factor as well as of the anti-neutrino flux.Comment: 9 pages, 9 figure