Calculation of Feynman loop integration and phase-space integration via auxiliary mass flow  

作　　者：Xiao Liu Yan-Qing Ma Wei Tao Peng Zhang 刘霄;马滟青;陶伟;张鹏(School of Physics and State Key Laboratory of Nuclear Physics and Technology,Peking University,Beijing 100871,China;Center for High Energy Physics,Peking University,Beijing 100871,China;Collaborative Innovation Center of Quantum Matter,Beijing 100871,China)

机构地区：[1]School of Physics and State Key Laboratory of Nuclear Physics and Technology,Peking University,Beijing 100871,China [2]Center for High Energy Physics,Peking University,Beijing 100871,China [3]Collaborative Innovation Center of Quantum Matter,Beijing 100871,China

出　　处：《Chinese Physics C》2021年第1期162-174,共13页中国物理C（英文版）

基　　金：Supported in part by the National Natural Science Foundation of China(11875071,11975029);the High-performance Computing Platform of Peking University。

摘　　要：We extend the auxiliary-mass-flow(AMF) method originally developed for Feynman loop integration to calculate integrals which also involve phase-space integration.The flow of the auxiliary mass from the boundary(∞) to the physical point(0+) is obtained by numerically solving differential equations with respective to the auxiliary mass.For problems with two or more kinematical invariants,the AMF method can be combined with the traditional differential-equation method,providing systematic boundary conditions and a highly nontrivial self-consistency check.The method is described in detail using a pedagogical example of e+e-→γ*→tt+X at NNLO.We show that the AMF method can systematically and efficiently calculate integrals to high precision.

关 键 词：phase-space integration perturbation theory MULTI-LOOP 

分 类 号：O172.2[理学—数学]