Direct extraction of one-loop integral coefficients

被引:259
作者
Forde, Darren [1 ]
机构
[1] Stanford Univ, Stanford Linear Accelerator Ctr, Stanford, CA 94309 USA
[2] Univ Calif Los Angeles, Dept Phys & Astron, Los Angeles, CA 90095 USA
来源
PHYSICAL REVIEW D | 2007年 / 75卷 / 12期
关键词
D O I
10.1103/PhysRevD.75.125019
中图分类号
P1 [天文学];
学科分类号
0704 ;
摘要
We present a general procedure for obtaining the coefficients of the scalar bubble and triangle integral functions of one-loop amplitudes. Coefficients are extracted by considering two-particle and triple unitarity cuts of the corresponding bubble and triangle integral functions. After choosing a specific parametrization of the cut loop momentum we can uniquely identify the coefficients of the desired integral functions simply by examining the behavior of the cut integrand as the unconstrained parameters of the cut loop momentum approach infinity. In this way we can produce compact forms for scalar integral coefficients. Applications of this method are presented for both QCD and electroweak processes, including an alternative form for the recently computed three-mass triangle coefficient in the six-photon amplitude A(6)(1(-),2(+),3(-),4(+),5(-),6(+)). The direct nature of this extraction procedure allows for a very straightforward automation of the procedure.
引用
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页数:20
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