发表机构
Lund University; University of Bern; Simrhythmia Research; Ruijl Research; Uppsala University; ELTE Eötvös Loránd University（隆德大学; 伯尔尼大学; Simrhythmia研究公司; Ruijl研究公司; 乌普萨拉大学; 厄特沃什·罗兰大学）
机构由 AI 辅助整理，请以论文原文为准。AI 中文总结
pyAmpliCol是基于AmpliCol策略的公共生成器，通过对称群快速傅里叶变换解决高多重度色干涉瓶颈，支持多模型与功能，可扩展树级矩阵元在对撞机相关计算的应用范围。
AI 中文摘要
树级矩阵元是对撞机事例产生的核心，但在额外的分辨辐射最为重要的区域，其计算成本会快速上升。我们提出pyAmpliCol，这是一个公共生成器，旨在将色分辨矩阵元的实际应用范围扩展到更高多重度。它基于AmpliCol的色有序离壳流策略，可快速访问单个领头色流，同时保留次领头或精确全色的选项。后者会引入自身的高多重度瓶颈：阶乘数量级的色序之间的密集干涉。pyAmpliCol通过对称群上的快速傅里叶变换解决了这种收缩问题，在保留精确色结果的同时避免了直接的两两求和。代表性的全色基准测试显示，与本文考虑的参考计算相比，其速度有显著提升。它支持标准模型过程和广泛的UFO模型，支持选定或求和的螺旋度、向量化评估以及可控的数值精度。它还提供色和自旋关联的玻恩量以及任意微扰阶的树级色连接，使同一框架可应用于局域减除和其他高阶应用。这些功能共同将高多重度矩阵元与其在事例产生、合并、部分子簇射和精确计算中的应用联系起来，整合在单个生成器中。
英文摘要
Tree-level matrix elements sit at the heart of collider event generation, but their cost rises rapidly just where additional resolved radiation becomes most important. We present pyAmpliCol, a public generator aimed at extending the practical reach of colour-resolved matrix elements to higher multiplicities. It builds on the colour-ordered, off-shell-current strategy of AmpliCol, providing fast access to individual leading-colour flows while retaining the option of next-to-leading or exact full colour. The latter introduces its own high-multiplicity bottleneck: the dense interference of factorially many colour orderings. pyAmpliCol addresses this contraction with a fast Fourier transform on the symmetric group, preserving the exact colour result while avoiding the direct pairwise sum. Representative full-colour benchmarks demonstrate substantial speedups over the reference calculations considered here. It supports Standard Model processes and a broad class of UFO models, selected or summed helicities, vectorised evaluation and controllable numerical precision. It further provides colour- and spin-correlated Born quantities and tree-level colour connections at arbitrary perturbative order, opening the same framework to local subtraction and other higher-order applications. Together, these capabilities connect high-multiplicity matrix elements to their use in event generation, merging, parton showers and precision calculations within a single generator.
Comments59 pages. Code and documentation: https://mg5amcnlo.github.io/pyamplicol
