Physics Beyond Standard Model with the CMS Pixel Detector

粒子物理的标准模型现在已经在许多层面上得到了证实。自从2012年发现希格斯玻色子以来，高能物理学的圣杯就是寻找超越标准模型(BSM)的新物理。该奖项集中于目前在瑞士日内瓦欧洲核子研究中心的大型强子对撞机(LHC)上运行的CMS实验。在大型强子对撞机上对希格斯玻色子性质的精确测量可以深入了解质量的性质和电弱对称破缺的性质，这将导致电磁相互作用部分表现为光，以及导致原子核β衰变的弱相互作用分离。大型强子对撞机可能会揭示出质量更轻的超对称性候选者，这是一种自然地解释弱电对称破坏的理论。对“丢失的能量”的精确测量可能会揭示许多未被发现的粒子的特征，其中一些可能是暗物质的候选者。能量缺失也可能是引力子在额外维度逃逸的原因，也可能是BSM中可能存在的其他奇异粒子的原因。这项研究的主要重点是利用新安装的CMS像素探测器的能力来寻找超对称性。这款新探测器具有额外的筒层和端盖层、精简的材料轮廓、可将LHC事件高堆积导致的数据损失降至最低的新读出芯片，以及优化的探测器布局，可在整个CMS伪快度范围内实现4像素命中覆盖。这些改进转化为更高的跟踪效率、更低的假跟踪率、更低的死区时间/数据丢失、更长的探测器寿命，所有这些都导致更好的Muon识别、b夸克标记、光子/电子识别、tau重建、改进的“粒子流”分析和遗漏能量重建。由于改进的b标记和更好的丢失能量估计而提高的信号选择效率是发现超对称性的分析程序的核心。这项工作还将包括设计和开发更多像素探测器升级的活动，同时保持对像素探测器业务的支持。制造、调试和维护最先进的硅探测器的这一挑战为物理和工程领域的劳动力发展提供了机会。该奖项提供的数据分析技术和相关算法、硬件仪器、网格计算、机器学习和大数据科学机会为学生提供了宝贵的经验和知识，使他们能够在学术界或私营部门追求成功的职业生涯。Quarknet外联活动进一步促进了与高中教师的合作，加强了波多黎各学校周围的教与学，并激励学生追求STEM纪律。这一奖项反映了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 has now been confirmed at many levels. Since the Higgs boson discovery in 2012, the holy grail of high energy physics is the search for new physics Beyond the Standard Model (BSM). This award is centered on the CMS experiment currently running at the Large Hadron Collider (LHC) at CERN in Geneva, Switzerland. The precise measurements of the properties of the Higgs boson at the LHC could give insight into the nature of mass and the nature of electroweak symmetry breaking, which causes the electromagnetic interaction, manifest in part as light, and the weak interaction responsible for beta decay of atomic nuclei to separate. The LHC might unveil lighter mass candidates for Supersymmetry, a theory that naturally explains electroweak symmetry breaking. The precise measurement of 'missing energy' could unveil signatures of many undiscovered particles, some of which could be candidates for Dark Matter. Missing energy could also account for the graviton escaping in extra-dimensions or for other exotic particles possibly expected in BSM.The primary focus of this research is to exploit the capabilities of the newly installed CMS pixel detector to pursue searches for Supersymmetry. This new detector has an extra barrel and endcap layers, a reduced material profile, a new readout chip to minimize data losses due to high pile-up of LHC events, and an optimized detector layout for 4-pixel-hit coverage over the full CMS pseudorapidity range. These improvements translate to higher tracking efficiencies, lower fake-track rates, lower dead-time/data-loss, an extended lifetime of the detector, all leading to better muon identification, b-quark tagging, photon/electron identification, tau reconstruction, improved "particle flow" analysis, and missing energy reconstruction. An improved signal selection efficiency due to improved b-tagging and better missing energy estimation is central to this analysis program to discover Supersymmetry. This effort will also include activities in design and development of additional pixel detector upgrades while maintaining support of Pixel Detector Operations. This challenge of building, commissioning, and maintaining a state-of-the-art silicon detector provides workforce development opportunities in physics and engineering. The data analyses techniques and related algorithms, hardware instrumentation, grid computing, Machine Learning and big data science opportunities carried out in this award give students valuable experience and knowledge enabling them to pursue successful careers in academia or the private sector. The Quarknet outreach activities further foster collaboration with high school teachers, strengthening teaching and learning around the schools in Puerto Rico and motivating students to pursue STEM disciplines.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.