Nonuniversality of Transverse Momentum Dependent Parton Distributions at Small x

We study the universality issue of the transverse momentum dependent parton distributions at small x, by comparing the initial and final state interaction effects in di-jet-correlations in pA collisions with those in deep inelastic lepton-nucleus scattering. We demonstrate the nonuniversality by performing an explicit calculation in a particular model where the multiple gauge boson exchange contributions are summed up to all orders. We comment on the implications of our results on the theoretical interpretation of dihadron correlation in dA collisions in terms of the saturation phenomena in deep inelastic lepton-nucleus scattering.