论文标题
朝着Openloops中的两环自动化
Towards two-loop automation in OpenLoops
论文作者
论文摘要
NLO散射幅度由全自动数值工具（例如Openloops）提供，用于广泛的过程。为了匹配当前和未来对撞机实验的数值精度，NNLO计算的较高精度至关重要，并且它们在类似工具中的自动化是非常可取的目标。在我们的方法中，D维的两环幅度分解为具有四维分子和（D-4）维剩余的Feynman积分。后者是通过与过程无关的合理反式插入到低环图中重建的，而第一个则表示为与张量系数收缩的环动量张量积分积分。在本文中，我们描述了[1]中首次介绍的一种完全通用的算法，用于这些张量系数的有效且数值稳定的结构。该算法在QED和QCD校正的OpenLoops框架中已完全实现。对于此实施，我们介绍了有关数值稳定性和CPU效率的绩效研究。
NLO scattering amplitudes are provided by fully automated numerical tools, such as OpenLoops, for a very wide range of processes. In order to match the numerical precision of current and future collider experiments, the higher precision of NNLO calculations is essential, and their automation in a similar tool a highly desirable goal. In our approach, D-dimensional two-loop amplitudes are decomposed into Feynman integrals with four-dimensional numerators and (D-4)-dimensional remainders. The latter are reconstructed through process-independent rational counterterm insertions into lower-loop diagrams, while the first are expressed as loop momentum tensor integrals contracted with tensor coefficients. In this article, we describe a completely generic algorithm, first presented in [1], for the efficient and numerically stable construction of these tensor coefficients. This algorithm is fully implemented in the OpenLoops framework for QED and QCD corrections to the Standard Model. For this implementation we present performance studies on numerical stability and CPU efficiency.
