Vector Meson Dominance and Vector Meson Production

Abstract

Against a background supported by the three pillars of emergent mass, this contribution challenges the fidelity of vector meson dominance as an instrument for relating the electromagnetic vector-meson (V) production reaction $e + p \to e^\prime + V + p$ to the hadronic process $V + p \to V + p$. It also describes a viable reaction model for exclusive photoproduction of light and heavy vector mesons from the proton, which exposes the $q\bar q$ content of the photon. That model's successes reveal that it is premature to link extant $V + p \to V + p$ data with, for instance, in-proton gluon distributions, the QCD trace anomaly, or pentaquark production. Improved reaction theory and more precise data are required before the validity of such links can objectively be assessed.