Global QCD Analysis and Electroweak Symmetry Breaking in High Energy Collider Phenomenology

高能对撞机现象学中的全局 QCD 分析和电弱对称破缺

• 批准号: 0855561
• 负责人: Chien-Peng Yuan
• 金额: $ 135万
• 依托单位: Michigan State University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2009
• 资助国家: 美国
• 起止时间: 2009-09-01 至 2015-08-31
• 项目状态: 已结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=0855561&HistoricalAwards=false
• 关键词: Global; QCD; Analysis; Electroweak; Symmetry

Current understanding of high energy physics is embodied in the Standard Model (SM). According to that theory, protons and neutrons, along with all other strongly interacting particles, are composed of even more fundamental particles called partons (quarks and gluons). Interactions between the partons are described by the theory of Quantum Chromodynamics (QCD). The proposed research involves continued refinement in understanding the interplay between QCD theory and experiment, which is necessary to deepen the understanding of QCD and to determine the probability distributions of the partons in the proton by global analysis. The resulting CTEQ Parton Distributions are essential to the interpretation of experiments at the world's leading high energy collider facilities: Fermilab (Batavia, IL), DESY (Hamburg, Germany), RHIC (Brookhaven, NY), and CERN (Geneva, Switzerland). The Electroweak sector of the SM is extremely successful in explaining and predicting experimental data spanning a range in energy from the atomic scale to the Z boson mass.However, one major aspect of the model remains to be elucidated: the mechanism of Electroweak Symmetry Breaking (EWSB), which generates masses for the W and Z bosons while leaving electromagnetic gauge symmetry intact. In the SM, EWSB is economically implemented through a single scalar particle called the Higgs boson. However, the SM cannot explain observations such as the hierarchical pattern of fermion masses, or the existence of dark matter; so it is widely believed that new measurements at very high energies, or very high precision, will soon turn up deviations from the SM that will point to new physics.A second part of the project represents continuation of research to probe the EWSB mechanism in high energy collisions. Special consideration is given to measuring the couplings of the top quark to W and Z gauge bosons and to (elementary or composite) Higgs boson(s); and to searching for the Higgs boson and determining its properties. These are prime objectives of experiments at the Fermilab Tevatron collider and the CERN Large Hadron Collider (LHC).The broader impacts of this project are as follows: The achievement of the project will contribute to understanding of the fundamental interactions in Nature. The project trains graduate students and postdoctoral fellows in theoretical high energy physics at MSU and at the CTEQ summer schools. It also provides opportunities for undergraduate students to participate in research through the REU program, and for high school teachers and middle school students to experience forefront research through Summer programs sponsored by MSU and the State of Michigan.

当前对高能物理的理解体现在标准模型（SM）中。根据该理论，质子和中子以及所有其他强相互作用的粒子，由更基本的粒子组成，称为部分子（夸克和胶子）。部分子之间的相互作用由量子色动力学（QCD）理论描述。拟议的研究涉及对 QCD 理论与实验之间相互作用的持续细化理解，这对于加深对 QCD 的理解并通过全局分析确定质子中部分子的概率分布是必要的。由此产生的 CTEQ 帕顿分布对于解释世界领先的高能对撞机设施的实验至关重要：费米实验室（伊利诺伊州巴达维亚）、DESY（德国汉堡）、RHIC（纽约布鲁克海文）和 CERN（瑞士日内瓦）。 SM 的电弱部分在解释和预测从原子尺度到 Z 玻色子质量的能量范围的实验数据方面非常成功。然而，该模型的一个主要方面仍有待阐明：电弱对称破缺 (EWSB) 的机制，它为 W 和 Z 玻色子产生质量，同时保持电磁规范对称性完好。在 SM 中，EWSB 通过称为希格斯玻色子的单个标量粒子经济地实现。然而，SM 无法解释诸如费米子质量的分层模式或暗物质的存在等观察结果；因此，人们普遍认为，在非常高的能量或非常高的精度下进行的新测量很快就会发现与 SM 的偏差，这将指向新的物理学。该项目的第二部分代表着继续研究，以探索高能碰撞中的 EWSB 机制。特别考虑测量顶夸克与 W 和 Z 规范玻色子以及（基本或复合）希格斯玻色子的耦合；寻找希格斯玻色子并确定其性质。这些是费米实验室 Tevatron 对撞机和 CERN 大型强子对撞机 (LHC) 实验的主要目标。该项目的更广泛影响如下： 该项目的成就将有助于理解自然界的基本相互作用。该项目在密歇根州立大学和 CTEQ 暑期学校培训理论高能物理学的研究生和博士后。它还为本科生提供通过 REU 项目参与研究的机会，并为高中教师和中学生提供通过密歇根州立大学和密歇根州赞助的暑期项目体验前沿研究的机会。