Measurement of inelastic J/psi and psi ' photoproduction at HERA

The cross sections for inelastic photoproduction of J/psi, and psi' mesons have been measured in ep collisions with the ZEUS detector at HERA, using an integrated luminosity of 468 pb(-1) collected in the period 1996-2007. The psi' to J/psi cross section ratio was measured in the range 0.55 1 GeV. Theoretical predictions within the non-relativistic QCD framework including NLO colour-singlet and colour-octet contributions were compared to the data, as were predictions based on the k(T)-factorisation approach.