Off-shell and factorization effects in exclusive vector-meson production

It is shown that the universality of the initial and final state interactions responsible for the transition between the on- and off-mass shell states leads to the energy independence of the ratio of exclusive ρ electroproduction cross section to the total cross section. It is demonstrated that the above universality and explicit mass dependence of the exponent in the power-like energy behavior of the cross-section obtained in the approach based on unitarity is in a quantitative agreement with the high-energy HERA experimental data. We discuss also HERA results on angular distributions of vector-meson production