Multiple-pomeron splitting in QCD - a novel antishadowing effect in coherent dijet production on nuclei

We discuss the salient features of the Pomeron splitting mechanism for cohe rent diffraction of pions into hard dijets on nuclei. Our findings include antishadowing multiple-Pomeron splitting expansion for diffractive amplitud es, exact cancellation of nuclear attenuation, and broadening/antishadowing effects to leading twist and parameter-free perturbative calculation of nu clear-rescattering-driven higher twist correction. We comment on the pQCD i nterpretation of the E791 results on diffractive dijets. (C) 2000 MAIK "Nau ka/Interperiodica".