On the Subleading-Soft Behaviour of QCD Amplitudes
arXiv:1411.1669 · doi:10.1103/PhysRevD.91.065018
Abstract
We elaborate on the radiative behaviour of tree-level scattering amplitudes in the soft regime. We show that the sub-leading soft term in single-gluon emission of quark-gluon amplitudes in QCD is controlled by differential operators, whose universal form can be derived from both on-shell recursion relation and gauge invariance, as it was shown to hold for graviton- and gluon-scattering.
24 pages, 4 figures