Title: Sudakov evolution without unitarity Show Chinese title

Title: 无幺正性的Sudakov演化

Abstract: We present a method for sampling singular functions defined on (nested) multi-particle phase spaces, based on a generalisation of parton-shower phase-space generation techniques. At the heart of the method are three key ingredients: 1) the Sudakov sampling by which shower-style calculations sweep across phase space in an ordered manner, from hard to soft; 2) the sequential nesting of multiparticle phase spaces; and 3) the factorisations obeyed by singular multiparton amplitudes on the edges of these phase spaces. We demonstrate a C++ implementation of the proposed algorithm, dubbed Sunshine, for hadronic Z decays, and use it to test the tree-level accuracy of the Vincia sector shower through $\mathcal{O}(\alpha_s^2)$. Show Chinese abstract

Abstract: 我们提出了一种在（嵌套）多粒子相空间上定义的奇异函数采样方法，该方法基于对部分子簇射相空间生成技术的推广。 该方法的核心有三个关键要素：1）Sudakov 采样，通过这种采样方式，类似簇射的计算以有序的方式从硬到软遍历相空间；2）多粒子相空间的顺序嵌套；以及 3）这些相空间边缘上的奇异多部分子振幅所遵守的因子化性质。 我们展示了一个名为 Sunshine 的提议算法的 C++ 实现，用于强子 Z 粒子衰变，并利用它通过$\mathcal{O}(\alpha_s^2)$测试 Vincia 区域簇射的树级精度。