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Experimental Study of Heavy Flavor and CP Violation with the LHCb Experiment at the CERN LHC Collider

在 CERN LHC 对撞机上使用 LHCb 实验进行重味和 CP 破坏的实验研究

基本信息

批准号：
2012793
负责人：
Abolhassan Jawahery
金额：
$ 135万
依托单位：
University of Maryland, College Park
依托单位国家：
美国
项目类别：
Continuing Grant
财政年份：
2020
资助国家：
美国
起止时间：
2020-06-30 至 2023-06-29
项目状态：
已结题

来源：
https://www.nsf.gov/awardsearch/showAward?AWD_ID=2012793&HistoricalAwards=false
关键词：
Experimental Study Heavy Flavor CP

项目摘要

A major focus of experimental particle physics research is on the search for physics beyond the Standard Model. Flavor physics plays a key role in this endeavor via precision measurements of ﬂavor processes sensitive to quantum loop effects, which complement direct searches at the highest energy accelerators. The physics reach of the LHCb experiment at the CERN LHC collider includes precision measurements of rare decays and matter-antimatter asymmetry in the charm quark and the bottom quark systems. At the current level of precision, these measurements impose severe constraints on the energy scale and the structure of new physics models. However, areas of deviations from the Standard Model are emerging, including signs of lepton non-universality in radiative and semi-leptonic B decays, which are highly sensitive to the presence of new scalar particles. The precision of future measurements in some key areas is expected to reach the required sensitivity to clarify these anomalies or further strengthen the deviations from the Standard Model predictions. These results could, in conjunction with studies at high energies, point the way to the structure of the physics beyond the Standard Model. This project involves a Maryland experimental particle physics group study of heavy flavor and CP violation with the LHCb experiment. It includes the development and construction of off-detector electronics for the upstream tracker for the LHCb detector upgrade and the installation and commissioning of the tracker, as well as major participation in the physics analysis of recorded and future LHCb data. The physics analysis effort is focused on measurements related to two current anomalies in the decays of B mesons: hints of departure from Lepton Flavor Universality in semileptonic B decays and the longstanding “Kaon pion” puzzle, where the measured CP asymmetries in the family of B to Kaon plus pion decays deviate from expectations. These anomalies, if confirmed, could be due to the imprints of new physics on flavor processes. Several data analysis techniques will be developed and used, including the use of machine learning. The ﬁndings of new sources of CP violation beyond the SM will have a profound impact on the understanding of the origin of baryon-antibaryon asymmetry and the ﬁeld of cosmology. The studies of ﬂavor processes will also yield precision information on the decay properties of the bottom and charmed hadrons, serving as a powerful testing ground for the predictions of lattice QCD calculations. The group’s detector upgrade eﬀort provides excellent opportunities for training undergraduate students in experimental and engineering techniques. The group works closely with an outreach program run by the physics and astronomy departments at the University of Maryland, the GRAD-MAP, which is aimed at providing research and training opportunities for undergraduates from underrepresented groups in the Maryland and Washington area community colleges. The group plans to expand this eﬀort to data analysis with the LHCb data by introducing students to advanced data handling and analysis techniques, such as machine learning.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.

实验粒子物理学研究的一个主要焦点是寻找标准模型之外的物理。风味物理学在这一努力中发挥着关键作用，通过精确测量对量子回路效应敏感的风味过程，补充了在最高能量加速器上的直接搜索。欧洲核子研究中心大型强子对撞机LHCb实验的物理范围包括精确测量魅夸克和底夸克系统中的稀有衰变和物质-反物质不对称性。在目前的精度水平下，这些测量对新物理模型的能量尺度和结构施加了严格的限制。然而，偏离标准模型的领域正在出现，包括辐射和半轻子B衰变中轻子非普适性的迹象，这对新标量粒子的存在非常敏感。一些关键领域的未来测量精度预计将达到所需的灵敏度，以澄清这些异常或进一步加强与标准模型预测的偏差。这些结果可以与高能研究相结合，为超越标准模型的物理结构指明方向。该项目涉及马里兰州实验粒子物理组的重味和CP破坏与LHCb实验的研究。它包括为LHCb探测器升级的上游跟踪器开发和建造探测器外电子设备，安装和调试跟踪器，以及主要参与记录和未来LHCb数据的物理分析。物理分析工作的重点是测量相关的两个当前异常的B介子的衰变：从轻子味普适性偏离半轻子B衰变和长期存在的"K介子"之谜，其中测量的CP不对称性在家庭的B K介子加π介子衰变偏离预期的暗示。这些异常现象，如果得到证实，可能是由于新物理学对风味过程的影响。将开发和使用若干数据分析技术，包括使用机器学习。在SM之外发现新的CP破坏源将对理解重子-反重子不对称性的起源和宇宙学领域产生深远的影响。对夸克过程的研究也将产生关于底强子和粲强子衰变性质的精确信息，为格点QCD计算的预测提供强有力的试验场。该小组的探测器升级项目为本科生提供了实验和工程技术方面的培训机会。该小组与马里兰州大学物理学和天文学系的外展计划密切合作，该计划旨在为马里兰州和华盛顿地区社区学院代表性不足的群体的本科生提供研究和培训机会。该小组计划通过向学生介绍先进的数据处理和分析技术（如机器学习），将该奖项扩展到LHCb数据的数据分析。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。