HIGH-ENERGY PHOTOPRODUCTION OF CHARMED STATES.

Photoproduction experiments studying the formation of bound and open charm have been carried out over the last ten years using both real and virtual photon beams. The early measurements were usually interpreted using the vector meson dominance model (VDM). More recent efforts have focused on precise measurements of the energy dependence, elasticity, and the Q**2 dependence of both bound and open charm production. These data are now interpreted through a perturbative model based on quantum chromodynamics (QCD); the model is known as photon-gluon fusion (PGF). This paper compares experimental data with the current theoretical models.