Energy dependence of exclusive vector-meson production in ep   interactions at HERA
  The energy dependence of exclusive vector meson (V) production is studied using the ZEUS data. The SU(4) universality of V cross sections in the $Q^2+M_V^2$ scale is tested. The energy dependence of the ratio of the cross sections for V production to the total $\gamma^*p$ cross section is compared with expectations based on pQCD and Regge approaches. 
Aharon Levy (for the ZEUS Collaboration)