Soft gluon-quark-antiquark emission in QCD hard scattering

Abstract

We consider the radiation of a soft gluon ($g$) and a soft quark-antiquark ($q\bar{q}$) pair in QCD hard scattering. In the soft limit the scattering amplitude has a singular behaviour that is factorized and controlled by a soft current, which has a process-independent structure in colour space. We evaluate the soft $gq\bar{q}$ current at the tree level for an arbitrary multiparton scattering process. The irreducible correlation component of the current includes strictly non-abelian terms and also terms with an abelian character. Analogous abelian correlations appear for soft photon-lepton-antilepton emission in QED. The squared current for soft $gq\bar{q}$ emission produces colour dipole and colour tripole interactions between the hard-scattering partons. The colour tripole interactions are odd under charge conjugation and lead to charge asymmetry effects. We consider the specific applications to processes with two and three hard partons, and we discuss the structure of the corresponding charge asymmetry contributions. We also generalize our QCD results to the cases of QED and mixed QCD$\times$QED radiative corrections.

30 pages, 1 figure. arXiv admin note: text overlap with arXiv:2108.13309

References in corpus (6)

• Hard-Soft-Collinear Factorization to All Orders
• Two-loop splitting amplitudes and the single-real contribution to inclusive Higgs production at N3LO
• May the four be with you: Novel IR-subtraction methods to tackle NNLO calculations
• Triple collinear splitting functions at NLO for scattering processes with photons
• Multiple soft radiation at one-loop order and the emission of a soft quark-antiquark pair
• Polarized triple-collinear splitting functions at NLO for processes with photons

Cited by in corpus (8)

• NNLO subtraction for any massless final state: a complete analytic expression
• The parton-level structure of $e^{+}{e}^{-}$ to 2 jets at N${}^3$LO
• Revisiting the double-soft asymptotics of one-loop amplitudes in massless QCD
• Identifying regions in wide-angle scattering via graph-theoretical approaches
• Soft Theorem to Three Loops in QCD and $\mathcal{N}=4$ Super Yang-Mills Theory
• The parton-level structure of Higgs decays to hadrons at N${}^3$LO
• Jet production at electron-positron colliders at next-to-next-to-next-to-leading order in QCD
• Catani's generalization of collinear factorization breaking