发表机构
Università di Torino; INFN, Sezione di Torino; The University of Edinburgh（都灵大学; 意大利国家核物理研究所都灵分部; 爱丁堡大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
本文从天球视角回顾QCD红外发散，将软电流与软颜色关联映射到天球上的二维共形场论，并探讨了单次与多次发射对天球理论结构的约束，揭示红外QCD与二维理论间的深刻联系。
AI 中文摘要
非阿贝尔红外辐射既可以视为QCD唯象学的实际要素，也可视为规范理论长距离结构的窗口。在过去十年中，人们发展了一种关于红外现象的新视角：软电流被视为由天球上实现的渐近对称性产生，而软颜色关联同样源于球面上的二维共形场论。在本文中，我们简要回顾了这一方法的现状。我们首先从标准体图像开始，介绍无质量散射振幅的红外因子化，然后展示普适红外信息如何映射到天球上的标记点。特别地，软颜色偶极子奇点通过球面上自由玻色子理论中的顶点算子关联函数在所有阶上得到重现。接着，我们研究软胶子电流，并展示体结果如何约束超越自由场极限的天球理论结构。对于单次发射，我们注意到偶极子型圈贡献中的所有对数都可以吸收到强耦合常数的尺度选择中。对于多次发射，我们展示了新兴的混合螺旋度天球算子乘积展开必须按能量分数加权，这会破坏全纯因子化，并在连续共线极限下阻碍结合性。这些结果揭示了熟悉的红外QCD物理与天球上二维理论动力学之间的显著联系。
英文摘要
Non-abelian infrared radiation can be seen as both a practical ingredient for QCD phenomenology and a window on the long-distance structure of gauge theories. During the last decade, a novel viewpoint was developed on infrared phenomena: soft currents are seen as arising from asymptotic symmetries realised on the celestial sphere, and soft colour correlations similarly emerge from a two-dimensional conformal field theory on the sphere. In this contribution, we briefly review the status of this approach. We begin with the standard bulk picture, presenting the infrared factorisation of massless scattering amplitudes, and then we show how universal infrared information gets mapped to marked points on the celestial sphere. In particular, soft colour-dipole singularities are reproduced to all orders by a correlator of vertex operators in a free-boson theory on the sphere. We then proceed to study soft-gluon currents, and show how bulk results constrain the structure of the celestial theory beyond the free-field limit. For single emission, we note that all logarithms in dipole-like loop contributions can be absorbed into the choice of scale for the strong coupling. For multiple emission, we show how the emerging mixed-helicity celestial operator product expansion must be weighted by energy fractions, breaking holomorphic factorisation and obstructing associativity under successive collinear limits. These results illustrate a remarkable connection between the familiar physics of infrared QCD and the dynamics of a two-dimensional theory on the celestial sphere.
CommentsProceedings of the conference QCD@Work 2026
