论文标题

用CMS开放数据解开夸克和胶子

Disentangling Quarks and Gluons with CMS Open Data

论文作者

Komiske, Patrick T., Kryhin, Serhii, Thaler, Jesse

论文摘要

我们使用CMS实验中的公共对撞机数据分别研究夸克和Gluon喷气机。我们的分析基于2011年在大型强子对撞机上收集的7 TEV的2.3/fb的质子 - 蛋白碰撞。我们通过伪造剪切定义了两个非重叠样品 - 带有| ETA |的中央喷气机| <0.65和带有| eta |的前向飞机> 0.65-并采用喷气主题建模来提取可分开类别的单个分布。在某些假设(例如样本独立性和相互不可约性)下,这些类别对应于最近提出的操作定义给出的“夸克”和“ gluon”喷气机。我们考虑了从中央和正向数据集提取降低性因子的许多不同方法,从中可以确定每个样品中夸克喷气机的分数。对统计不确定性的最大稳定性和鲁棒性是通过基于参数化接收器操作特征(ROC)曲线的端点的新方法来实现的。为了减轻探测器效应,否则会引起中央和正向喷气机之间的非物理差异,我们使用Omnifold方法执行中心值展开。为了证明这种方法的力量,我们提取夸克和gluon喷气样品的固有维度,这些维度表现出Casimir缩放,这是从强度订购的极限所预期的。据我们所知,这项工作是将全相空间展开到真实对撞机数据的首次应用,也是主题建模的第一个应用程序之一,是在LHC提取单独的夸克和Gluon分布。

We study quark and gluon jets separately using public collider data from the CMS experiment. Our analysis is based on 2.3/fb of proton-proton collisions at 7 TeV, collected at the Large Hadron Collider in 2011. We define two non-overlapping samples via a pseudorapidity cut -- central jets with |eta| < 0.65 and forward jets with |eta| > 0.65 -- and employ jet topic modeling to extract individual distributions for the maximally separable categories. Under certain assumptions, such as sample independence and mutual irreducibility, these categories correspond to "quark" and "gluon" jets, as given by a recently proposed operational definition. We consider a number of different methods for extracting reducibility factors from the central and forward datasets, from which the fractions of quark jets in each sample can be determined. The greatest stability and robustness to statistical uncertainties is achieved by a novel method based on parametrizing the endpoints of a receiver operating characteristic (ROC) curve. To mitigate detector effects, which would otherwise induce unphysical differences between central and forward jets, we use the OmniFold method to perform central value unfolding. As a demonstration of the power of this method, we extract the intrinsic dimensionality of the quark and gluon jet samples, which exhibit Casimir scaling, as expected from the strongly-ordered limit. To our knowledge, this work is the first application of full phase space unfolding to real collider data, and one of the first applications of topic modeling to extract separate quark and gluon distributions at the LHC.

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