Fate of k⊥-factorization for hard processes in nuclear environment

Large thickness of heavy nuclei brings in a new scale into the pQCD description of hard processes in nuclear environment. The familiar linear k⊥-factorization breaks down and must be replaced by a new concept of the nonlinear k⊥-factorization introduced in [N.N. Nikolaev, W. Schafer, B.G. Zakharov and V.R. Zoller, J. Exp. Theor. Phys. 97 (2003) 441]. I demonstrate the salient features of nonlinear k⊥-factorization on an example of hard dijet production in PIS off heavy nuclei. I also discuss briefly the non-linear BFKL evolution for gluon density of nuclei.