Photoproduction of ω mesons from complex nuclei targets

Measurements are presented of the cross sections for omega meson photoproduction at a mean energy of 3.9 GeV from nuclear targets of D, Be, C, Al, Cu, Ag, Au. An optical and Glauber model analysis of the coherent cross sections has been performed to obtain the ω-nucleon cross section, σ_ωN, and the photon-omega coupling constant γ_ω²/4π. Our results are summarised in table 4. We find good agreement with the quark model prediction that σ_ωN = σ_?N, and with the value of γ_ω2/4π determined from the storage ring experiments and from an earlier complex nuclei measurement. However, we disagree with more recent complex nuclei measurements which found a high value of γ_ω²/4π.