Disentangling MEC and single-pion-production contributions

Disentangle the relative contributions of virtual pion exchange through two-particle–two-hole meson-exchange currents and real single-pion production to the dip-region strength in inclusive electron–nucleus scattering, despite final-state interactions.

Background

The paper finds that the dip-region strength between the quasielastic and Delta-resonance peaks receives contributions from both two-particle–two-hole meson-exchange currents involving virtual pion exchange and processes involving explicit single-pion production. Because these mechanisms can overlap after final-state interactions, assigning the measured strength uniquely to either process is conceptually difficult.

The authors state that no model-independent prescription is currently available for separating final-state-interaction-corrected single-pion-production contributions from meson-exchange-current contributions. Resolving this ambiguity is important for avoiding double counting and for obtaining a physically consistent description of inclusive electron- and neutrino–nucleus scattering.