%0 Journal Article
%T Multiple soft radiation at one-loop order and the emission of a soft quark-antiquark pair
%A Catani, S.
%A Cieri, L.
%J European Physical Journal C
%D 2022
%V 82
%N 2
%I Springer
%@ 1434-6044
%G English
%F Catani+Cieri2022
%O WOS:000749553600001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5098), last updated on Tue, 08 Feb 2022 08:38:00 +0000
%X We consider the radiation of two or more soft partons in QCD hard-scattering at one-loop order. The corresponding scattering amplitude is singular, and the singular behaviour is controlled by a process-independent soft current. Using regularization in d = 4 – 2 epsilon space-time dimensions, we explicitly evaluate the ultraviolet and infrared divergent (epsilon-pole) terms of the one-loop soft current for emission of an arbitrary number of soft partons in a generic hard-scattering process. Then we consider the specific case of soft quark-antiquark (q (q) over bar) emission and we compute the one-loop current by including the finite terms. We find that the one-loop soft-q (q) over bar current exhibits a new type of transverse-momentum singularity, which has a quantum (absorptive) origin and a purely non-abelian character. At the squared amplitude (cross section) level, this transverse-momentum singularity produces contributions to multijet production processes in hadron collisions. The one-loop squared current also leads to charge asymmetry terms, which are a distinctive features of soft-q (q) over bar radiation. We also extend these results to the cases of QED and mixed QCDxQED radiative corrections for soft fermion-antifermion emission.
%R 10.1140/epjc/s10052-022-10001-z
%U https://arxiv.org/abs/2108.13309
%U https://doi.org/10.1140/epjc/s10052-022-10001-z
%P 97 - 27pp