Quantum effects and color transparency in charmonium photoproduction on nuclei

We develop a rigorous quantum-mechanical treatment of color transparency effects in diffractive photoproduction of $\overline{c}c$ pairs on nuclei. The evolution of the $\overline{c}c$ wave function during propagation through a nucleus is more a considerable distortion of its form than a trivial attenuation. One of the manifestations of the quantum effects is a nuclear antishadowing of the ${\psi }^{\prime }$ yield, i.e., transparency above one. However, considerable nuclear shadowing is predicted for the photoproduction of $\frac{J}{\psi }$, which has a much smaller absorption cross section than ${\psi }^{\prime }$.