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

目前对高能物理的理解体现在标准模型（SM）中。根据这一理论，质子和中子，以及所有其他强相互作用的粒子，是由更基本的粒子组成的，叫做部分子（夸克和胶子）。部分子之间的相互作用用量子色动力学（QCD）理论描述。本文的研究需要不断完善对量子cd理论与实验相互作用的理解，这对于深化对量子cd的理解和通过全局分析确定质子中各部分的概率分布是必要的。由此产生的CTEQ部分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（巴达维亚，伊利诺伊州），DESY（汉堡，德国），RHIC（布鲁克海文，纽约州）和欧洲核子研究中心（日内瓦，瑞士）。SM的电弱部分在解释和预测跨越从原子尺度到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，它在保持电磁规范对称不变的情况下为W和Z玻色子产生质量。在SM中，EWSB是通过称为希格斯玻色子的单个标量粒子经济地实现的。然而，SM不能解释诸如费米子质量的等级模式或暗物质的存在等观测结果；因此，人们普遍认为，在非常高的能量或非常高的精度下，新的测量将很快发现与SM的偏差，这将指向新的物理学。该项目的第二部分是继续研究高能碰撞中的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。这些都是费米实验室Tevatron对撞机和欧洲核子研究中心大型强子对撞机（LHC）实验的主要目标。该项目的广泛影响如下：该项目的实现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暑期学校培养理论高能物理学的研究生和博士后。它还为本科生提供了通过REU项目参与研究的机会，并为高中教师和中学生提供了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。

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.