Quark model and vector dominance relation in hadronic quasi-two-body reactions

The Additive Quark Model relates Δ to vector meson production. The predictions of this model are formulated and compared to the data in a number of reactions involving vector mesons and Δ production. In all cases excellent agreement with data has been found. With the quark model we generalize the vector dominance relation proposed by Cho and Sakurai to the Δ case. Experiments agree well with the predictions. Empirically the predictions appear to be valid also in other reactions like A1 production. (author)