Diffractive Photoproduction of Jets with a Direct Pomeron Coupling at   HERA
  We investigate in detail the effect of a direct pomeron coupling to quarks on the production of jets in $ep$ scattering with almost real photons. Jet production via a direct pomeron coupling is compared with the resolved--pomeron mechanism. We consider both direct and resolved photoproduction. Rapidity and transverse momentum distributions are calculated and compared with preliminary H1 and ZEUS data. 
B.A. Kniehl, H.-G. Kohrs and G. Kramer