Subleading logarithms in QCD hard scattering

We discuss the resummation of corrections from the elastic limit (partonic threshold) in hadronic QCD hard-scattering cross sections, such as heavy quark production. We recall why these corrections can be large even at high orders in perturbation theory, and describe their resummation to arbitrary logarithmic accuracy, generalizing resummation in the Drell-Yan and other electroweak processes. Resummation is based on the factorization of soft gluons, whose dynamics is then generated by gauge field path-ordered exponentials, linked by color-dependent vertices. The renormalization of these composite vertices determines subleading logarithms. We illustrate our results for the case of heavy quark production by light quark annihilation.