Department of Physics, Harvard University, Cambridge, Massachusetts 02138, USA.
Phys Rev Lett. 2010 Jul 9;105(2):022001. doi: 10.1103/PhysRevLett.105.022001. Epub 2010 Jul 6.
A new class of observables is introduced which aims to characterize the superstructure of an event, that is, features, such as color flow, which are not determined by the jet four-momenta alone. Traditionally, an event is described as having jets which are independent objects; each jet has some energy, size, and possible substructure such as subjets or heavy flavor content. This description discards information connecting the jets to each other, which can be used to determine if the jets came from decay of a color-singlet object, or if they were initiated by quarks or gluons. An example superstructure variable, pull, is presented as a simple handle on color flow. It can be used on an event-by-event basis as a tool for distinguishing previously irreducible backgrounds at the Tevatron and the LHC.
引入了一类新的可观量，旨在描述事件的超结构，即由喷注四动量本身无法确定的特征，如颜色流。传统上，事件被描述为具有独立的喷注；每个喷注都有一定的能量、大小和可能的亚结构，如子喷注或重味内容。这种描述丢弃了连接喷注之间的信息，这些信息可以用来确定喷注是否来自色单物体的衰变，或者它们是否是由夸克或胶子引发的。作为颜色流的一个简单处理方法，拉变量是一个超结构变量的示例。它可以在事件的基础上用作在 Tevatron 和 LHC 上区分以前不可约背景的工具。
