Diffractive photoproduction of vector mesons at large momentum transfer
  Diffractive photoproduction of rho, phi and J/psi was studied in the BFKL approach to hard colour singlet exchange. Differential cross sections, the energy dependence and spin density matrix elements were calculated and compared to data from HERA. The overall description of data is reasonably good, except of the single flip amplitude which has the wrong sign. Importance of chiral odd components of the photon is stressed. 
R. Enberg, J. Forshaw, L. Motyka and G. Poludniowski