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arXiv 2308.14701hep-phhep-th
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圈积分的张量约化

Tensor reduction of loop integrals

Charalampos Anastasiou, Julia Karlen, Matilde Vicini

AI总结:

针对 Passarino-Veltman 张量约化中的大型方程组对角化问题,本文利用横截度规张量基与正交对偶基映射给出任意张量积分的闭式公式,并通过 QCD 2→2 散射至三圈的 Feynman 图示例验证应用。

摘要:

使用 Passarino-Veltman 方法将张量积分约化为标量积分时,其计算成本主要由大型方程组的对角化决定。这些方程组的规模取决于可由度规和外动量构造的独立张量元的数量。在本文中,我们给出了任意张量积分中这一对角化问题的闭式解。我们采用一种张量基,其构造单元是外动量矢量以及一个与外动量空间横截的度规张量。通过将基元映射到一个正交对偶基的元素,可得到这些基张量的标量积分系数。该映射可由一个形式上类似 Wick 定理中算符排序的公式简洁表达。最后,我们给出示例,展示我们的张量约化公式在 QCD 2→2 散射过程的 Feynman 图中的应用,具体最高达到三圈。

英文摘要:

The computational cost associated with reducing tensor integrals to scalar integrals using the Passarino-Veltman method is dominated by the diagonalisation of large systems of equations. These systems of equations are sized according to the number of independent tensor elements that can be constructed using the metric and external momenta. In this article, we present a closed-form solution of this diagonalisation problem in arbitrary tensor integrals. We employ a basis of tensors whose building blocks are the external momentum vectors and a metric tensor transverse to the space of external momenta. The scalar integral coefficients of the basis tensors are obtained by mapping the basis elements to the elements of an orthogonaldual basis. This mapping is succinctly expressed through a formula that resembles the ordering of operators in Wick's theorem. Finally, we provide examples demonstrating the application of our tensor reduction formula to Feynman diagrams in QCD $2 \to 2$ scattering processes, specifically up to three loops.

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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