The longitudinal cross section of vector meson electroproduction

We analyze electroproduction of light vector mesons (V = rho,phi and omega) at small Bjorken-x in the handbag approach, in which the process factorizes into general parton distributions and partonic subprocesses. The latter are calculated in the modified perturbative approach in which the transverse momenta of the quark and antiquark forming the vector meson are retained and Sudakov suppression is taken into account. Modeling the generalized parton distributions through double distributions and using simple Gaussian wavefunctions for the vector mesons, we compute the longitudinal cross sections at large photon virtualities. The results are in fair agreement with the findings of recent experiments performed at HERA and HERMES.