The first calculation of fractional jets
The first calculation of fractional jets
复制标题
分数射流的第一次计算
DOI：
10.1007/jhep05(2015)008
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发表时间：
2015
影响因子：
5.4
通讯作者：
J. Walsh
中科院分区：
文献类型：
--
作者：
D. Bertolini;J. Thaler;J. Walsh
在对撞机物理学中，射流算法是一种普遍存在的工具，用于将粒子聚集成离散的射流对象。事件形状提供了表征射流的另一种方式，并且可以使用“没有射流的射流”的框架来定义射流多重性事件形状，其可以采用分数值。在本文中，我们进行了第一次分析研究的分数喷流多重数的E-jet在e+e−碰撞的背景下。我们使用固定阶QCD来理解αs2阶的喷注截面，并引入一个候选因子分解定理来捕捉某些高阶效应。由此产生的分布有一个混合射流算法/事件形状的行为，同意部分子簇射蒙特卡罗发电机。可观测的双头喷流不满足普通的软共线分解，双头喷流截面具有许多独特的特征，包括不存在共线分解和存在纯粹非全局的软分解。此外，我们发现新的分歧连接到排放之间的能量共享，这让人想起在其他应用中遇到的快度分歧。考虑到这些有趣的性质，分数喷流多重性，我们主张未来的测量和计算的强子对撞机，如大型强子对撞机的喷流。
A bstractIn collider physics, jet algorithms are a ubiquitous tool for clustering particles into discrete jet objects. Event shapes offer an alternative way to characterize jets, and one can define a jet multiplicity event shape, which can take on fractional values, using the framework of “jets without jets”. In this paper, we perform the first analytic studies of fractional jet multiplicity Ñjet in the context of e+e− collisions. We use fixed-order QCD to understand the Ñjet cross section at order αs2, and we introduce a candidate factorization theorem to capture certain higher-order effects. The resulting distributions have a hybrid jet algorithm/event shape behavior which agrees with parton shower Monte Carlo generators. The Ñjet observable does not satisfy ordinary soft-collinear factorization, and the Ñjet cross section exhibits a number of unique features, including the absence of collinear logarithms and the presence of soft logarithms that are purely non-global. Additionally, we find novel divergences connected to the energy sharing between emissions, which are reminiscent of rapidity divergences encountered in other applications. Given these interesting properties of fractional jet multiplicity, we advocate for future measurements and calculations of Ñjet at hadron colliders like the LHC.