Studies in Elementary Particle Physics

基本粒子物理研究

• 批准号: 2310072
• 负责人: Morris Swartz
• 金额: $ 210万
• 依托单位: Johns Hopkins University
• 依托单位国家: 美国
• 项目类别: Continuing Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-08-01 至 2026-07-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310072&HistoricalAwards=false
• 关键词: Studies; Elementary; Particle; Physics

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.

粒子物理学的标准模型描述了自50多年前提出以来观察到的许多微观物理现象。 特别是，最引人注目的预测之一是希格斯玻色子的预测，这是在2012年在欧洲核子研究中心大型强子对撞机上观察到的。 尽管标准模型取得了成功，但它可能是不完整的。 它没有描述暗物质，暗物质是宇宙质量密度的主要部分。 它不能解释为什么普通物质比反物质占优势。 只有一个希格斯玻色子的理论在数学上是不稳定的，这表明在更大的质量尺度上有希格斯兄弟或新的物理过程发生。该项目的目标之一是提高我们对希格斯耦合的认识，当存在更重的兄弟姐妹时，希格斯耦合可能会偏离标准模型的预测。 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。 其他的目标是直接寻找LHC可能产生的更重的状态，并寻找它们对大质量标准模型过程的可能影响。 这个项目推进了我们对粒子物理学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到最先进的检测技术，计算技术和数据分析技术。 这些训练有素的学生和博士后追求学术和非学术领域的职业生涯。 该项目还举办了一个非常成功的Quarknet中心，为大约25名马里兰州地区高中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。该项目建立在一个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及其性质的表征。希格斯计划的重点是金四轻子衰变通道，但也将其他衰变通道纳入生产机制相关的测量。在壳层和离壳层生产中的运动学信息被用来精确测量希格斯玻色子的质量、宽度、量子数、CP性质，以及更一般地，在有效场论的框架内希格斯与矢量玻色子和费米子相互作用的张量结构。该项目包括寻找观测态和其他类似态的较重兄弟，如顶夸克共振，W'和Z'玻色子，奇异引力子，leptoquark和激发夸克和胶子。这些都是标准模型的许多扩展所预测的。识别和重建这些状态的衰变所需的技术是由支持者使用以前的NSF支持开发的。 特别是，搜索将使用跟踪增强，喷气子结构技术，机器学习技术和复杂的可能性变量。最后，该项目支持CMS探测器的操作和LHC高亮度升级的新探测器技术研究的技术贡献。业务贡献基于目前使用的技术或从目前使用的技术衍生而来。对探测器升级研究的贡献是基于为支持当前操作而开发的工具。该奖项反映了NSF的法定使命，并通过使用基金会的知识价值和更广泛的影响审查标准进行评估，被认为值得支持。