Measurement of J/psi photoproduction at large momentum transfer at HERA

                       ZEUS Collaboration

                          Abstract

The proton-dissociative diffractive photoproduction of J/psi mesons has been studied in 
ep collisions with the ZEUS detector at HERA using an integrated luminosity of 112 pb. 
The cross section is presented as a function of the photon-proton centre-of-mass energy 
and of the squared four-momentum transfer at the proton vertex. The results are compared 
to perturbative QCD calculations.