Studies of Quark-Gluon Physics

现在一个公认的事实是，核子、质子和中子是由更基本的称为夸克的粒子组成的。这笔拨款支持的主要物理计划是研究核子的夸克结构。关于这种夸克结构的细节还需要更多的信息。特别有趣的一个方面是质子中存在反夸克，这是量子力学的结果。一项名为Seaquest的实验利用费米实验室加速器中的高能质子来研究这些反夸克在核子和原子核中的分布。这项实验将在确定反夸克分布方面达到前所未有的精度。除了粒子物理领域，这些分布在宇宙学中也很有用，因为它们试图了解银河系尺度上的物质。除了科学目标之外，拟议的探测器调试、数据获取和分析活动将继续为本科生和研究生提供教育和研究经验。这项为期三年的研究计划将利用费米实验室的Drell-yan反应研究核子和原子核中反向下夸克和反向上夸克的比率。在高动量分数下，这些鲜为人知的反夸克分布可能提供了对经典核物理中众所周知的“pion云”模型的部分子理解。核靶中的反应也将被用于研究夸克的能量损失。科罗拉多州小组已接近完成海洋光谱仪的新跟踪探测器，提供更大的接受度和更高的速率能力，并计划完成、安装和调试该探测器。

It is now a well-established fact that nucleons, protons and neutrons, are made up of more elementary particles called quarks. The main physics program supported by this grant is to study of the quark structure of nucleons. More information is needed about the details of this quark structure. One aspect that is particularly interesting is the existence of anti-quarks in the proton, which is a consequence of quantum mechanics. An experiment called Seaquest uses high-energy protons from the Fermilab accelerator to study these anti-quark distributions in the nucleon and in nuclei. This experiment will achieve unprecedented accuracy in the determination of the anti-quark distributions. Beyond the field of particle physics, these distributions are useful in cosmology as they seek to understand matter at the galactic scale. Beyond the scientific goals, the proposed detector commissioning, data acquisition and analysis activities will continue to offer education and research experience to undergraduates and graduate students.This three-year research program will study the ratio of anti-down quarks to anti-up quarks in the nucleon and in nuclei using the Drell-Yan reaction at Fermilab. At high momentum fraction these poorly known anti-quark distributions may provide a partonic understanding of the well known "pion cloud" model of classical nuclear physics. The reaction in nuclear targets will also be used to study quark energy loss. The Colorado group has nearly completed a new tracking detector for the Seaquest spectrometer, providing a larger acceptance and higher rate capabilities, and plans to complete, install, and commission this detector.