Exclusive electroproduction of vector mesons at HERMES

The exclusive diffractive production of light vector mesons (rho(0),phi) in the intermediate energy region at moderate Q(2) is described. The longitudinal components of cross sections on hydrogen target are shown in comparison with theoretical calculations based on the generalized parton distributions to identify the production mechanisms of vector mesons. In the case of nitrogen target for fixed coherence length a rise of the nuclear transparency with Q(2) is observed for both coherent and incoherent rho(0) production. This is in agreement with theoretical calculations that include the effect of color transparency.