Transverse momentum resummation at small x for the Tevatron and LHC

Analysis of semi-inclusive DIS hadroproduction suggests broadening of transverse momentum distributions at $x$ below a few $10^{-3}$, which can be modeled in the Collins-Soper-Sterman formalism by a modification of impact-parameter-dependent parton densities. We discuss the consequences of such a modification for the production of electroweak bosons at hadron-hadron colliders. If substantial small-$x$ broadening is observed in forward Z boson production in the Tevatron Run-2, it will strongly affect predicted transverse momentum distributions for W, Z, and Higgs boson production at the Large Hadron Collider.