Deeply Virtual Neutrino Scattering at DUNE

We calculate the helicity structure of Compton–Bethe–Heitler interference in ν ̄μp → μ+nγ in a deeply virtual region relevant to the DUNE near detector. An analytic generalized- parton-distribution input is compared with a phenomenological input and with a hybrid whose local weak form factors are identical to the analytic ones. The fixed-current compari- son isolates changes in the hadronic amplitude while leaving lepton radiation unchanged. We derive an exact magnitude–phase decomposition, including its mixed contribution, and evalu- ate it with finite-muon-mass kinematics, specified nucleon helicities and a common flux. The symmetric allocation attributes approximately 64.7% of the integrated interference change to magnitude redistribution and 35.3% to phase changes, although phase changes dominate at the selected 10 GeV benchmark. Near equality of the integrated hadronic squares therefore does not establish a phase-only mechanism. Both crossing combinations of the four transition distributions are retained. The CFF phases are calculated from the full GPD convolutions, retaining their dependence on the distribution shapes and the different scattering denomi- nators. The interference response separates real Compton form factors into cosine moments and imaginary parts into sine moments for the stated tree-level calculation. We quantify the resulting limitation on independent form-factor combinations and repeat the analysis with a second conserved completion.