Vector-meson electroproduction from generalized vector dominance

Including destructively interfering off-diagonal transitions of diffraction-dissociation type, we arrive at a formulation of GVD for exclusive vector-meson production in terms of a continuous spectral representation of dipole form. The transverse cross-section, σT,γ∗p→Vp, behaves asymptotically as 1/Q4, while RV≡σL,γ∗p→Vp/σT,γ∗p→Vp becomes asymptotically constant. Contributions violating s-channel helicity conservation stay at the level established in low-energy photoproduction and diffractive hadron–hadron interactions. The data on ρ0-meson production from the Fermilab E665 Collaboration and on φ- and ρ0-meson production from HERA are found to be in agreement with these predictions.