The contribution of the hadronic component of the photon into the $D^{\ast }$-meson photoproduction at HERA

Abstract

In the framework of the vector dominance model (VDM) new contribution into the cross-section of $D^{\ast }$-meson photoproduction at HERA has been estimated. This contribution is due to the interaction of the virtual vector $c\bar{c}$-mesons from photon with the proton. It has been shown that the mechanism under discussion plays the essential role for all values of transverse momentum of $D^{\ast }$-mesons at HERA. Taking into account for the contribution of this mechanism improves the description of the experimental cross section distribution.

12 pages, LATEX file, 5 ps-figures; changed LATEX style; estimated the model uncertainty