Evidence for the flavor singlet axial anomaly related effects in phi-mesonelectromagnetic production at large momentum transfers

The gluonic contributions to the conventional PCAC formulas due to flavor s inglet axial anomaly have been instrumental in explaining the mass of the e ta' and providing a plausible explanation for solving the spin crisis. We s how that they also play an important role in the description of photo- and electroproduction of vector mesons at low energy and high momentum transfer s. We calculate the contributions of this type to phi -meson electromagneti c production in a model, which contains also a soft pomeron, and find agree ment with recent CLAS data. (C) 2001 Published by Elsevier Science B.V.