A COMPLETE O(ALPHA ALPHA S) CALCULATION OF THE PHOTON + 1 JET RATE IN E+E-ANNIHILATION
A COMPLETE O(ALPHA ALPHA S) CALCULATION OF THE PHOTON + 1 JET RATE IN E+E-ANNIHILATION
复制标题
电子湮灭中光子1射流速率的完整O(Alpha ALPHA S)计算
DOI：
10.1016/s0550-3213(97)00818-3
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发表时间：
1997
期刊：
影响因子：
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通讯作者：
E. Glover
中科院分区：
文献类型：
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作者：
A. Ridder;E. Glover
我们完整地计算了e+e−湮没到O(ααS)的光子+1喷注速率。虽然形式上属于微扰理论中的次前级计算，但这个计算包含了几个适用于喷流可观测性的次前级计算的成分。特别是，我们描述了通常使用的相空间切片方法的推广，以隔离当不止一个粒子未分辨时存在的奇点。在这种方法中，我们解析地评估了与以下双未解区域相关的奇点：三重共线、软/共线和双单共线构型以及来自虚图的共线极限的奇点。通过将我们的计算结果与欧洲核子研究中心Aleph合作的现有光子+1喷注速率数据相比较，我们确定了与过程无关的非微扰夸克到光子碎裂函数DQ→γ(z，μF)在O(ααS)处的次要级数。作为这一测量与我们改进的微扰计算相结合的第一次应用，我们确定了民主聚类法中孤立光子+1喷注截面与喷流分辨参数在次前级的依赖关系。对该观测数据的次前级修正是适度的，但改善了理论预测和实验数据之间的一致性。
We present a complete calculation of the photon + 1 jet rate in e+e−annihilation up to O (ααs). Although formally of next-to-leading order in perturbation theory, this calculation contains several ingredients appropriate to a next-to-next-to-leading order calculation of jet observables. In particular, we describe a generalization of the commonly used phase space slicing method to isolate the singularities present when more than one particle is unresolved. Within this approach, we analytically evaluate the singularities associated with the following double unresolved regions: triple collinear, soft/collinear and double single collinear configurations as well as those from the collinear limit of virtual graphs. By comparing the results of our calculation with the existing data on the photon + 1 jet rate from the ALEPH Collaboration at CERN, we make a next-to-leading order determination of the process-independent non-perturbative quark-to-photon fragmentation function Dq→γ(z, μF) at O (ααs). As a first application of this measurement allied with our improved perturbative calculation, we determine the dependence of the isolated photon + 1 jet cross section in a democratic clustering approach on the jet resolution parameter ycutat next-to-leading order. The next-to-leading order corrections to this observable are moderate but improve the agreement between theoretical prediction and experimental data.