Electroproduction and photoproduction of vector mesons and generalized vector-meson dominance

Using generalized vector-meson dominance, electroproduction and photoproduction of vector mesons is studied. The unnatural-parity-exchange part of ω′(1.2) production is estimated to be about 1/4 of that of ω production. The off-diagonal transition model suggests the suppression of diffractive ρ′(1.2) and ω′(1.2) production