报告题目：Renormalization of twist-two operators in covariant gauge to three loops in QCD

报告人：杨通智 博士

时 间：2023年2月23日上午10点

腾讯会议：869-624-800

邀请人：王 健 教授

报告摘要

The evolution of parton densities, which are crucial for making quantitative predictions in all high-energy hadron collider processes, is governed by the splitting functions. To determine the N3LO parton densities, which are becoming increasingly relevant with the inclusion of several hard matching coefficients at N3LO, it is necessary to know the 4-loop splitting functions. To make the computation possible and save computational resources, finding an efficient method to compute 4-loop splitting functions is of great importance. The method of computing off-shell matrix elements with a twist-two operator insertion is among the most efficient techniques. Nonetheless, the off-shell nature of external gluons poses renormalization issues related to gauge invariance. Addressing these concerns entails identifying all gauge-variant operators that mix with the physical twist-two operators. We recently introduced a new framework in which we systematically extract all gauge-variant operators. We applied this framework to rederive the unpolarized singlet splitting functions up to the three-loop order, and we demonstrated that our approach is valid to all loop orders. Furthermore, our framework enables the derivation of all-n operator Feynman rules, making it a unique and valuable contribution to the field.

报告人简介

Tongzhi Yang graduated from Zhejiang University in 2015 and obtained his Ph.D. there in 2020 under the supervision of Mingxing Luo and Huaxing Zhu. He is currently a postdoctoral researcher at the University of Zurich and a visitor at Michigan State University. His research focuses on high-precision predictions in perturbative QCD. He shows particular interest in applying differential equation methods and modern IBP reductions with finite-field techniques to compute various Wilson coefficients or universal anomalous dimensions, such as beam functions, soft functions, as well as splitting functions.

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