  To describe the transverse momentum spectrum of heavy color-singlet
production, the joint resummation of threshold and transverse momentum
logarithms is investigated. We obtain factorization theorems for various
kinematic regimes valid to all orders in the strong coupling, using
Soft-Collinear Effective Theory. We discuss how these enable resummation and
how to combine regimes. The new ingredients in the factorization theorems are
calculated at next-to-leading order, and a range of consistency checks is
performed. Our framework goes beyond the current next-to-leading logarithmic
accuracy (NLL).
