NSF-BSF: Searching for Physics Beyond the Standard Model at the LHCb Experiment

20世纪最重要的智力成就之一是粒子物理学标准模型（SM）的发展。这个模型成功地将当时已知的所有基本粒子划分为具有相似量子特性的等级。迄今为止，该模型的有效性已被欧洲核子研究中心大型强子对撞机发现的希格斯玻色子所证实。然而，目前存在的标准模型留下了许多关于宇宙的问题。这些问题包括为什么物质在宇宙中支配反物质（CP违反），基本成分、夸克和轻子的质量值，夸克之间和轻子之间混合的大小，以及暗物质的性质。大多数解释都需要新粒子、对称性或力的存在，我们称之为超越标准模型物理学（BSM）。这个项目的目的是寻找BSM物理。大型强子对撞机是世界上首屈一指的高能物理粒子加速器，目前在瑞士日内瓦附近的欧洲核子研究中心实验室运行，是回答这些BSM问题的最重要的设施之一。麻省理工学院的小组是LHCb的合作成员，LHCb是一个专门设计的实验，用于研究LHC中含有b或c夸克的强子的衰变，并寻找其他新的物质状态。LHCb的目标是通过检测含有这些夸克的强子的性质来识别自然界中的新物理。新的物理学，或者新的力，可以通过尚未发现的粒子来体现，它们的存在将改变含有b和c夸克的强子的衰变速率和CP违反不对称性，从而允许间接观察到新的现象。此外，LHCb还为量子色动力学（QCD）的涌现现象学研究和寻找新的gev尺度(即。“低质量”)BSM粒子，可能是暗物质的组成部分。正是在这个研究领域，麻省理工学院的研究小组在开发基于机器学习算法的新触发策略以识别和选择感兴趣的物理方面发挥着主导和基础作用，但也在对可能包含假设的“黑暗”粒子（如暗光子或轴子样粒子）的相互作用进行分析方面发挥着重要作用。通过美国-以色列两国科学基金会（NSF-BSF）与以色列理工学院的合作，该项目加强了与这些暗部门研究相关的分析活动。麻省理工学院- lhcb小组开发的机器学习算法以开源软件包的形式提供，并被许多其他研究小组使用。此外，该组织还在麻省理工学院推出了备受认可的国际大师班项目，该项目将当地高中生带到麻省理工学院校园，了解高能物理研究的兴奋之处。该奖项反映了美国国家科学基金会的法定使命，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。

One of the major intellectual achievements of the 20th century was the development of the Standard Model (SM) of particle physics. This model succeeded in classifying all of the elementary particles known at the time into a hierarchy of groups having similar quantum properties. The validity of this model to date was confirmed by the discovery of the Higgs boson at the Large Hadron Collider at CERN. However, the Standard Model as it currently exists, leaves open many questions about the universe. These include why matter dominates over anti-matter in the Universe (CP violation), the values of the masses of the fundamental constituents, the quarks and the leptons, the size of the mixings among the quarks, and separately among the leptons, and the properties of dark matter. Most explanations require the presence of new particles, symmetries or forces, which we call Beyond the Standard Model Physics (BSM). This project is designed to pursue searches for BSM physics. The LHC is the premier High Energy Physics particle accelerator in the world and is currently operating at the CERN laboratory near Geneva Switzerland, one of the foremost facilities for answering these BSM questions. The Massachusetts Institute of Technology group is a collaboration member of LHCb, an experiment designed specifically to study the decays of hadrons containing b or c quarks at the LHC and to search for other new states of matter. The goal of LHCb is to identify new physics in nature by examining the properties of hadrons containing these quarks. New physics, or new forces, can be manifest by particles, as yet to be discovered, whose presence would modify decay rates and CP violating asymmetries of hadrons containing the b and c quarks, and thus allow new phenomena to be observed indirectly. Additionally, LHCb is making contributions to the study of the emergent phenomenology of quantum chromodynamics (QCD), and to searches for new GeV-scale (i.e. "low mass") BSM particles, possibly components of the dark sector of matter. And it is in this research domain that the MIT group is playing a leading and fundamental role, both in the development of new trigger strategies based upon machine learning algorithms to identify and select the physics of interest, but also in conducting analyses of interactions that might contain hypothetical "dark sector" particles such as dark photons or axion-like particles. The analytical activities associated with these dark sector studies are enhanced in this program through collaboration with Technion in Israel, through the United States - Israel Binational Science Foundation (NSF-BSF) program. The machine learning algorithms developed by the MIT-LHCb group are available in open-source software packages and are being used by many other research groups. Additionally, the group has introduced at MIT the well-recognized International Masterclasses program, which brings local high school students to the MIT campus to learn about the excitement of high energy physics research.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.