2026-07-072026-07-07http://salesiana.dossiersoluciones.com/handle/123456789/49064Results on elastic vector meson production at HERA are presented in the framework of perturbative QCD. The energy dependence of the cross section for J/Psi photoproduction and for rho electroproduction is studied. A full polarisation analysis, including the measurement of the 15 elements of the spin density matrix and of R=sigma_L/sigma_T, is presented for rho electroproduction. Finally heavier vector mesons (Psi' and Upsilon) production is discussed.4 pages, 2 figures. Contribution to the proceedings of the "Rencontres de Moriond": 1999 QCD and High Energy Hadronic InteractionsHigh Energy Physics - Phenomenologytext