Caola Fabrizio, Melnikov Kirill, Röntsch Raoul
CERN, Theoretical Physics Department, Geneva, Switzerland.
IPPP, Durham University, Durham, UK.
Eur Phys J C Part Fields. 2017;77(4):248. doi: 10.1140/epjc/s10052-017-4774-0. Epub 2017 Apr 18.
We discuss a modification of the next-to-next-to-leading order (NNLO) subtraction scheme based on the residue-improved sector decomposition that reduces the number of double-real emission sectors from five to four. In particular, a sector where energies and angles of unresolved particles vanish in a correlated fashion is redundant and can be discarded. This simple observation allows us to formulate a transparent iterative subtraction procedure for double-real emission contributions, to demonstrate the cancellation of soft and collinear singularities in an explicit and (almost) process-independent way and to write the result of a NNLO calculation in terms of quantities that can be computed in four space-time dimensions. We illustrate this procedure explicitly in the simple case of [Formula: see text] gluonic corrections to the Drell-Yan process of [Formula: see text] annihilation into a lepton pair. We show that this framework leads to fast and numerically stable computation of QCD corrections.
我们讨论了一种基于残差改进扇区分解的次下一个领头阶（NNLO）减法方案的修正，该修正将双实发射扇区的数量从五个减少到四个。特别地，一个未解析粒子的能量和角度以相关方式消失的扇区是冗余的，可以被舍弃。这一简单的观察使我们能够为双实发射贡献制定一个透明的迭代减法程序，以一种明确且（几乎）与过程无关的方式证明软和共线奇点的抵消，并根据可以在四个时空维度中计算的量来写出NNLO计算的结果。我们在[公式：见正文]湮灭成轻子对的Drell-Yan过程的[公式：见正文]胶子修正的简单情况下明确说明了这一程序。我们表明，该框架导致了对QCD修正的快速且数值稳定的计算。
