We calculate the one-loop correction to the soft-gluon current with massive fermions. This current is process independent and controls the singular behavior of one-loop massive QCD amplitudes in the limit when one external gluon becomes soft. The result derived in this work is the last missing process-independent ingredient needed for numerical evaluation of observables with massive fermions at hadron colliders at the next-to-next-to-leading order.
We consider the radiation of three soft gluons in a generic process for multiparton hard scattering in QCD. In the soft limit the corresponding scattering amplitude has a singular behaviour that is factorized and controlled by a colorful soft current. We compute the tree-level current for triple soft-gluon emission from both massless and massive hard partons. The three-gluon current is expressed in terms of maximally non-abelian irreducible correlations. We compute the soft behaviour of squared amplitudes and the colour correlations produced by the squared current. The radiation of one and two…
We complete the calculation of the three-gluon-emission contribution to the same-hemisphere part of the zero-jettiness soft function at next-to-next-to-next-to-leading order in perturbative QCD.
The leading order single inclusive soft gluon production in high energy proton-nucleus (pA) collisions has been studied by various approaches for more than two decades. The first correction due to the gluon saturation in proton was analytically attempted recently through a diagrammatic approach in which only partial results were obtained. An important feature of the first saturation correction is that it includes both initial state and final state interactions. In this paper, we present the complete result derived from the Color Glass Condensate framework. Our approach is to analytically solve…
We study soft-gluon corrections for the associated production of a single top quark and a $Z$ boson ($tqZ$ production) at hadron colliders. We find that the radiative corrections are dominated by soft-gluon emission. We calculate the approximate NNLO (aNNLO) cross section at LHC energies, including uncertainties from scale dependence and from parton distributions. We also calculate differential distributions in top-quark rapidity. We show that the aNNLO corrections are significant and they enhance the NLO cross section while decreasing theoretical uncertainties.
Infrared Singularities and Soft Gluon Resummation with Massive Partons
QCD散射振幅的红外发散可以从反常维数矩阵中导出，这也是软胶子发射产生的大振幅的重新计算的一个重要组成部分。本文报道了最近在双圈水平上对有质量部分子和无质量部分子的反常维数矩阵的解析计算，它描述了任意数量的有质量部分子和无质量部分子的散射振幅的双圈红外奇异性，并使软胶子能以次-次-首对数级重算.作为应用，我们计算了q qbar -> t tbar和gg -> t tbar散射振幅中的红外极点。
We study the gluon parton densities [parton distribution functions (PDFs), transverse momentum distributions (TMDs), generalized parton distributions (GPDs)] and form factors in soft-wall AdS/QCD. We show that the power behavior of gluon parton distributions and form factors at large values of the light-cone variable and large values of square momentum is consistent with quark counting rules. We also show that the transverse momentum distributions derived in our approach obey the model-independent Mulders-Rodrigues inequalities without referring to specific model parameters. All gluon parton d…
Formation of color-singlet gluon-clusters and inelastic diffractive scattering. Part I: Theoretical arguments and experimental indications for self-organized criticality (SOC) in systems of interacting soft gluons
