Semiempirical formula for electroweak response functions in the two-nucleon emission channel in neutrino-nucleus scattering

Understand

A semi-empirical formula for the electroweak response functions in the two-nucleon emission channel is proposed.

• The method consists in expanding each one of the vector-vector, axial-axial and vector-axial responses as sums of six sub-responses.
• These corresponds to separating the meson-exchange currents as the sum of three currents of similar structure, and expanding the hadronic tensor, as the sum of the separate contributions from each current plus the interferences between them.
• For each sub-response we factorize the coupling constants, the electroweak form factors, the phase space and the delta propagator, for the delta forward current.