Hadronic dijet imbalance and transverse-momentum-dependent parton distributions

We compare several recent theoretical studies of the single transverse-spin asymmetry in dijet correlations at hadron colliders. We show that the results of these studies are all consistent. To establish this, we investigate, in particular, the two-gluon exchange contributions to the relevant initial and final-state interactions in the context of a simplifying model. Overall, the results confirm that the dijet imbalance obeys, at best, a nonstandard or ``generalized'' transverse-momentum-dependent factorization.