Particle Physics - Measuring Charm Mixing Parameters in D-4h

粒子物理学 - 在 D-4h 中测量魅力混合参数

• 批准号: 2727067
• 金额: --
• 依托单位: University of Oxford
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2022
• 资助国家: 英国
• 起止时间: 2022 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2727067
• 关键词: Particle; Physics; Measuring; Charm; Mixing

The LHCb experiment has unsurpassed capabilities for studying the phenomena of mixing and CP violation in the charm system. Although mixing in charm decays was first observed around 15 years ago, it is highly desirable to improve the knowledge of the parameters that drive this process. CP violation in mixing-related phenomena has not been seen, and any observation at the current level of precision would be an indicator of New Physics.The student will embark on a programme of charm mixing and CP-violation measurements using four-body D decays, in particular the singly Cabibbo suppressed processes D->pi+pi-pi+pi- and K+K-pi+pi-. These decays have not been previously harnessed for such measurement, and offer promising sensitivity that is complementary to that obtainable from the two and three-body decays that have so far been exploited. He will do this with a model-independent approach that uses external knowledge of strong-phase parameters that are measured at the BESIII experiment in Beijing. The analysis will be based on data collected in Runs 1 and 2 of the LHC. Depending on the speed with which the analysis is conducted, he may also make a pilot measurement with early data collected in Run 3 with the upgraded LHCb detector, but this does not currently form part of the baseline plan. Another possible extension of the thesis work would be to contribute to the analysis of the BESIII data from which the strong-phase parameters are determined. Oxford is one of only two UK groups that are members of BESIII, and thus have unique access to these data.The TORCH is a novel time-of-flight Cherenkov detector that is proposed for installation in LHCb Upgrade II in a decade's time. A vigorous programme of R&D is required to arrive at a final design that will have the necessary performance. The student will play a central role in this development. Likely areas of involvement include the evaluation of front end electronics for prototypes and the final detector; participation in data taking and analysis in test beam campaigns; and the improvement of reconstruction code. He will also benchmark the impact that the TORCH detector will have on the physics reach of LHCb. Central to the success of TORCH is the performance of its photodetectors, and there will be close association with industry, in particular the UK firm Photek who have been heavily involved in the evolution of the TORCH project until now.

LHCb实验在研究Charm系统中的混合和CP破坏现象方面具有无可比拟的能力。虽然魅力衰退的混合是在大约15年前首次被观察到的，但人们非常希望提高对驱动这一过程的参数的了解。在与混合相关的现象中还没有看到CP破坏，任何在当前精度水平的观察都将是新物理的指示器。学生将开始一个使用四体D衰变的魅力混合和CP破坏测量程序，特别是单个Cabibbo被抑制的过程D-&gt；pi+pi-pi+pi-和K+K-pi+pi-。这些衰变以前从未被用于这种测量，并提供了有希望的灵敏度，这是对迄今已被利用的二体和三体衰变所获得的灵敏度的补充。他将使用一种独立于模型的方法来实现这一点，该方法使用在北京BESIII实验中测量的强相参数的外部知识。分析将基于大型强子对撞机第一次和第二次运行中收集的数据。根据分析的速度，他可能还会使用升级的LHCb探测器在运行3中收集的早期数据进行试点测量，但这目前不构成基线计划的一部分。本论文工作的另一个可能扩展将是对BESIII数据的分析，从这些数据中可以确定强相参数。牛津大学是英国仅有的两个加入BESIII的组织之一，因此可以独一无二地访问这些数据。TORCH是一种新型的飞行时间切伦科夫探测器，计划在十年后安装在LHCb Upgrade II上。需要一个强有力的研发计划，才能得出具有必要性能的最终设计。学生将在这一发展中发挥核心作用。可能参与的领域包括对原型和最终探测器的前端电子设备的评估；参与测试光束运动的数据获取和分析；以及改进重建代码。他还将对火炬探测器对LHCb物理覆盖范围的影响进行基准测试。TORCH成功的核心是其光电探测器的性能，而且将与业界密切合作，特别是英国公司Photek，他们到目前为止一直在大力参与TORCH项目的发展。