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arXiv 0912.3495hep-ph
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费曼圈积分的树图化数值计算

Numerical Evaluation of Feynman Loop Integrals by Reduction to Tree Graphs

Wolfgang Kilian, Tobias Kleinschmidt

摘要:

本文提出了一种基于Feynman树定理的Loop积分数值计算的新方法。用相空间积分法代替环积分。这种积分可以与普通相空间的Monte-Carlo积分一起执行,避免了被积函数内部循环评估的耗时嵌套,并直接导致NLO事件生成。我们系统地构建减法,必要的取消紫外线发散和额外的阈值奇点在相空间中出现的数值计算。红外奇异点可以用标准方法处理。作为概念证明,我们将该方法应用于QED中的NLO Bhabha散射,并构造了相应的NLO Monte Carlo事件发生器。

英文摘要:

We present a new method for the numerical evaluation of loop integrals which is based on the Feynman Tree Theorem. The loop integrals are replaced by phase-space integration over fictitious extra on-shell particles. This integration can be performed alongside with the Monte-Carlo integration of ordinary phase space, avoiding the time-consuming nesting of loop evaluation inside the integrand, and directly leading to NLO event generation. We systematically construct subtractions, necessary to cancel both ultraviolet divergences and the extra threshold singularities in phase-space which arise in the numerical evaluation. Infrared singularities can be dealt with by standard methods. As a proof of concept, we apply the method to NLO Bhabha scattering in QED and construct the corresponding NLO Monte Carlo event generator.

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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