Effective transverse momentum in multiple jet production at hadron colliders

We consider the class of inclusive hadron collider processes in which several energetic jets are produced, possibly accompanied by colorless particles [such as Higgs boson(s), vector boson(s) with their leptonic decays, and so forth]. We propose a new variable that smoothly captures the N+1 to N-jet transition. This variable, that we dub kTness, represents an effective transverse momentum controlling the singularities of the N+1-jet cross section when the additional jet is unresolved. The kTness variable offers novel opportunities to perform higher-order calculations in quantum chromodynamics by using nonlocal subtraction schemes. We study the singular behavior of the N+1-jet cross section as kTness→0 and, as a phenomenological application, we use the ensuing results to evaluate next-to-leading-order corrections to H+jet and Z+2-jet production at the LHC. We show that kTness performs extremely well as a resolution variable and appears to be very stable with respect to hadronization and multiple-parton interactions.