Studies in Elementary Particle Physics

粒子物理的标准模型描述了自50多年前提出以来所观察到的许多微观物理现象。特别是，最壮观的预测之一是2012年在CERN大型强子对撞机上观察到的希格斯玻色子的预测。尽管标准模型取得了很大成功，但它很可能是不完整的。它没有描述暗物质，暗物质是宇宙质量密度的主要部分。它没有解释为什么普通物质凌驾于反物质之上。只有一个希格斯玻色子的理论在数学上是不稳定的，这表明有希格斯兄弟姐妹或新的物理过程在更大的质量尺度上发生。这个项目的目标之一是提高我们对希格斯耦合的了解，当存在更重的兄弟姐妹时，希格斯耦合可能会与标准模型的预测略有偏离。也可能存在违反电荷共轭宇称对称性的非标准耦合，这可以解释宇宙的物质支配。其他目标是直接搜索在大型强子对撞机上可能产生的较重的状态，并搜索它们对高质量标准模型过程的可能影响。这个项目促进了我们对粒子物理学中的一个关键方向的理解，以及我们对宇宙基本物理定律的理解。它使本科生、研究生和博士后研究员接触最先进的探测器技术、计算技术和数据分析技术。这些训练有素的学生和博士后都在学术和非学术领域追求职业生涯。该项目还拥有一个非常成功的Quarknet中心，该中心为马里兰州地区约25名高中STEM教师提供专业发展机会。该项目是CERN大型强子对撞机(LHC)CMS实验中的实验粒子物理研究计划。该项目建立在一项正在进行的研究计划的基础上，该计划导致了希格斯玻色子的发现和对其性质的表征。希格斯计划的重点是黄金四轻子衰变通道，但也将其他衰变通道纳入与产生机制相关的测量。在有效场论的框架下，利用壳层内和壳外产生的运动学信息来精确测量希格斯玻色子的质量、宽度、量子数、CP性质，以及更广泛地说，希格斯与矢量玻色子和费米子相互作用的张量结构。该项目包括搜索观察到的状态和其他类似状态的更重的兄弟姐妹，如顶夸克共振、W‘和Z’玻色子、奇异引力子、轻夸克以及受激发的夸克和胶子。这些是通过标准模型的许多扩展来预测的。识别和重建这些状态衰变所需的技术是由支持者利用之前的NSF支持开发的。特别是，搜索将使用跟踪增强、喷气式子结构技术、机器学习技术和复杂的似然变量。最后，该项目为CMS探测器的运行和研究大型强子对撞机高亮度升级的新探测器技术做出了技术贡献。业务贡献基于当前正在使用的技术或源自当前正在使用的技术。对探测器升级研究的贡献是基于为支持目前的操作而开发的工具。该奖项反映了NSF的法定使命，并通过使用基金会的智力优势和更广泛的影响审查标准进行评估，被认为值得支持。

The Standard Model of particle physics describes many of the micro-physical phenomena that have been observed since it was proposed over 50 years ago. In particular, one of the most spectacular predictions was the prediction of the Higgs boson, which was observed in 2012 at the CERN Large Hadron Collider. For all of its success, the Standard Model is likely incomplete. It does not describe the dark matter, which is the dominant part of the mass density of the universe. It does not explain why ordinary matter dominates over antimatter. The theory with a single Higgs boson is mathematically unstable, which suggests that there are Higgs siblings or new physical processes occurring at larger mass scales. One of the goals of this project is to improve our knowledge of the Higgs couplings, which can deviate by small amounts from the predictions of the Standard Model when heavier siblings exist. There can also be non-standard couplings that violate the Charge Conjugation Parity symmetry, which could explain the matter domination of the universe. Other goals are to search directly for the heavier states that could be produced at the LHC and to search for their possible effects on high mass Standard Model processes. This project advances our understanding of one of the key directions in particle physics and of our understanding of the basic physical laws of the universe. It exposes undergraduate students, graduate students, and postdoctoral fellows to state of the art detector technologies, computing technologies, and data analysis techniques. Those highly trained students and postdocs pursue careers in both academic and non-academic fields. The project also hosts a very successful Quarknet center that provides professional development opportunities for a community of about 25 Maryland area high school STEM teachers.This project is a program of experimental particle physics research within the CMS experiment at the CERN Large Hadron Collider (LHC). The project builds upon an ongoing program of research that led to the discovery of the Higgs boson and the characterization of its properties. The focus of the Higgs program is on the golden four-lepton decay channel, but also incorporating other decay channels into production mechanism related measurements. Kinematic information in both on-shell and off-shell production is used to make precision measurements of the Higgs boson mass, width, quantum numbers, CP properties, and more generally, the tensor structure of Higgs interactions with vector bosons and fermions within the framework of effective field theory. The project includes searches for heavier siblings of the observed state and other look-alike states such as top quark resonances, W' and Z' bosons, exotic gravitons, leptoquarks, and excited quarks and gluons. These are predicted by many extensions of the Standard Model. The techniques needed to identify and reconstruct the decays of these states were developed by the proponents using previous NSF support. In particular, the searches would use tracking enhancements, jet substructure techniques, machine learning techniques, and sophisticated likelihood variables. Finally, this project supports technical contributions to the operation of the CMS detector and to the study of new detector technology for high luminosity upgrades of the LHC. The operational contributions are based on techniques that are currently in use or are derived from those currently in use. The contributions to the study of detector upgrades are based on tools that were developed to support the present operation.This award reflects NSF's statutory mission and has been deemed worthy of support through evaluation using the Foundation's intellectual merit and broader impacts review criteria.