Exclusive Electroproduction of Vector Mesons at HERMES Original Research Article

The exclusive diffractive production of light vector mesons (ρ0,ϕ) in the intermediate energy region at moderate Q2 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 Q2 is observed for both coherent and incoherent ρ0 production. This is in agreement with theoretical calculations that include the effect of color transparency.