ar X iv : h ep - p h / 01 10 26 8 v 1 1 9 O ct 2 00 1 Gluonic effects in vector meson photoproduction at large momentum transfers

The gluonic pole has been instrumental in explaining the mass of the η ′ and providing a plausible explanation for solving the spin crisis. We show that it also plays an important role in the description of the photoproduction of vector mesons at high momentum transfers at JLab energies. Recently the CLAS Collaboration at JLab has published new data on ρ-and φ-meson photoproduction at large momentum transfers [1, 2]. The main goal of these data is to help understand the OZI rule violation mechanism in strong interactions. The gluonic pole was introduced in [3] to describe features of OZI violation in the pseudoscalar meson nonet and to explain the large mass of η ′-meson. Recently it has been shown that this pole provides also a natural explanation of proton spin problem [4]. In here we consider the gluonic pole contribution to vector meson photoproduction off the nucleon. In QCD the anomalous gluonic axial current