J/￠ PRODUCTION AT HERA

摘要

Elastic and inelastic 3/ij) photoproduction have been measured at ZEUS. Elastic i/4) production from virtual photons with Q2 > 7 GeV2 has also been measured. Elastic production cannot be interpreted along the traditional Vector Dominance Model and Regge parametrisation of hadron-hadron scattering. QCD inspired models better describe the results. Inelastic events have been studied in the range z < 0.8, where z is the ratio between the J/4> and the incoming virtual photon energies in the proton rest frame. The cross sections are found in agreement with NLO pQCD calculations.