Unraveling the flux-averaged neutrino–nucleus cross section

The interpretation of the nuclear cross sections measured using accelerator neutrino beams involves prohibitive difficulties, arising primarily from the average over the incoming neutrino flux. The broad energy distribution of the beam particles severely hampers the determination of the energy transfer to the nuclear target, the knowledge of which is needed to pin down the dominant reaction mechanism. Overcoming this problem requires the development of a theoretical approach suitable to describe neutrino interactions at energies ranging from hundreds of MeV to few GeV. In this paper, it is argued that the approach based on factorisation of the nuclear cross section and the Green’s function formalism provides a consistent framework for the calculation of neutrino–nucleus interactions in both the quasi-elastic and inelastic channels. The near-degeneracy between theoretical models based on different assumptions, and the use of electron scattering data to advance the understanding of neutrino-nucleus cross sections are also discussed