Radiative decays, photoproduction and total cross section of the ψ particles

Abstract

It is pointed out that the coupling characterizing the ψ-γ vertex must change substantially between the limits, ψ on mass-shell which occurs in ψ→e+ e- and photon on mass-shell which is relevant in radiative decays like ψ→ππγ, ψ→ηγ and photoproduction of ψ. This has the consequence that the value of ψN total cross section must be larger than what is inferred from the use of naive vector dominance in photoproduction. © 1976 Indian Academy of Sciences.