  We consider the class of inclusive hadron collider processes in which several
energetic jets are produced, possibly accompanied by colourless 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 $k_T^{\rm ness}$, represents an
effective transverse momentum controlling the singularities of the $N+1$-jet
cross section when the additional jet is unresolved. The $k_T^{\rm ness}$
variable offers novel opportunities to perform higher-order calculations in
Quantum Chromodynamics (QCD) by using non-local subtraction schemes. We study
the singular behavior of the $N+1$-jet cross section as $k_T^{\rm ness}\to 0$
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 $k_T^{\rm ness}$ performs extremely well as a resolution
variable and appears to be very stable with respect to hadronization and
multiple-parton interactions.

High Energy Physics - Phenomenology