Multiple Scattering Theory for the Photoproduction of Vector Mesons off Nuclei

The integrated cross section for the incoherent photoproduction of vector mesons on nuclei $\gamma^* A \to VX$, $X\not=A$, is calculated within Glauber theory and as a function of the photon energy. The inverse of the longitudinal momentum transfer is called coherence length $l_c$ and depends on the virtuality and the energy of the photon. Nuclear transmission factors strongly depend on $l_c/R_A$ ($R_A$ is the nuclear radius) and this effect may interfere with the search for color transparency effects.