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arXiv 0807.3705hep-ph
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使用BlackHat进行单循环计算

One-Loop Calculations with BlackHat

C. F. Berger, Z. Bern, L. J. Dixon, F. Febres Cordero, D. Forde, H. Ita, D. A. Kosower, D. Maitre

摘要:

我们描述了BlackHat,一个自动化的C++程序计算单回路振幅,并在其建设中使用的技术。这些方法包括酉性方法和在壳递归。其他成分是紧凑的解析公式树振幅四维螺旋状态。该程序计算振幅数值,使用解析公式只为树振幅,递归的起点,和循环积分。我们利用最近开发的壳方法评估系数的循环积分,特别是离散傅立叶投影作为一种手段,提高数值稳定性。我们通过计算QCD中六、七、八胶子振幅的数值结果,并与已知的解析结果进行比较,说明了这种方法具有良好的数值稳定性。

英文摘要:

We describe BlackHat, an automated C++ program for calculating one-loop amplitudes, and the techniques used in its construction. These include the unitarity method and on-shell recursion. The other ingredients are compact analytic formulae for tree amplitudes for four-dimensional helicity states. The program computes amplitudes numerically, using analytic formulae only for the tree amplitudes, the starting point for the recursion, and the loop integrals. We make use of recently developed on-shell methods for evaluating coefficients of loop integrals, in particular a discrete Fourier projection as a means of improving numerical stability. We illustrate the good numerical stability of this approach by computing six-, seven- and eight-gluon amplitudes in QCD and comparing against known analytic results.

机构、总结、中文摘要均由AI分析而来,可能存在错误,请以论文正文为准。

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