Cross sections for elastic photoproduction of J/psi and Y mesons are presen
ted. For J/psi mesons the dependence on the photon-proton centre-of-mass en
ergy W-gamma p is analysed in an extended range with respect to previous me
asurements of 26 less than or equal to W-gamma p less than or equal to 2.85
GeV. The measured energy dependence is parameterized as sigma(gamma p) pro
portional to W-gamma p(delta) with delta = 0.83 +/- 0.07. The vp UP YP diff
erential cross section d sigma/dt for J/psi mesons is derived, its dependen
ce on W-gamma p and on t is analysed and the effective trajectory (in terms
of Regge theory) is determined to be alpha(t) = (1.27 +/- 0.05) + (0.08 +/
- 0.17) . t/GeV2. Models based on perturbative QCD and on pomeron exchange
are compared to the data. (C) 2000 Elsevier Science B.V. All rights reserve
d.