Correlated charm pairs at the LHCb Experiment

LHCb 实验中的相关魅力对

• 批准号: 2888673
• 金额: --
• 依托单位: University of Liverpool
• 依托单位国家: 英国
• 项目类别: Studentship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=studentship-2888673
• 关键词: Correlated; charm; pairs; LHCb; Experiment

The Standard Model of particle physics has proven to be one of the most successful theories in modern physics, providing an excellent description of electromagnetism and the strong and weak interactions. Yet, it still leaves many questions unanswered, such as the apparent matter-antimatter asymmetry in the universe. For this asymmetry to occur, both C (charge conjugation) and P (parity) symmetries must be violated in the interaction of fundamental particles.While the Standard Model allows CP violation to occur, it fails to fully account for the matter-antimatter imbalance on a cosmological scale, necessitating the developement of physics beyond the Standard Model. To this end, the main goals of flavour physics include searching for new sources of CP violation, and performing precise measurements of Standard Model parameters using decays of heavy flavour (containing b or c quarks) particles.A particularly promising phenomenon in the area of charm physics is the decay of particles with definite C and P eigenvalues into correlated DoDo pairs. The correlations in the DoDo system enable the direct measurement of T (time-reversal) symmetry in the system. As CP violation has been observed in the charm system, a direct measurement of T symmetry would allow for a test of CPT symmetry, which, if broken, would clearly point to physics beyond the Standard Model. Moreover, such correlated charm pairs could reduce systematic uncertainties on amplitude analyses of B meson decays by constraining the possible resonances. This in turn could enable us to better study the properties of new types of hadrons, such as exotic mesons and tetraquarks.The LHCb experiment is one of the four major detectors at CERN, optimised for the study of heavy flavour particles. The unique capabilities of the detector provide an excellent platform with which to search for new physics using correlated charmed hadrons. Using samples of decays collected during runs 2 and 3 of the LHCb experiment, I will attempt to reconstruct DoDo systems in a C=+1 eigenstate and extract the corresponding lineshape in the DoDo invariant mass spectrum. This allows the yields of DoDo pairs in their CP eigenstates to be determined in subsequent analyses, and is an instrumental step in measuring T violation in correlated charm systems. Eventually, these same charm systems can also provide key constraints on CP violation in the beauty system. Additionally, I will also perform a feasibility study to quantify the effects of including correlated charm pairs in amplitude analyses using a Monte-Carlo simulated sample of decays.

粒子物理学的标准模型已被证明是现代物理学中最成功的理论之一，它提供了对电磁学和强弱相互作用的极好描述。然而，它仍然留下了许多未解之谜，例如宇宙中明显的物质-反物质不对称性。标准模型允许电荷共轭对称和宇称对称同时被破坏，但标准模型不能完全解释物质-反物质在宇宙学尺度上的不平衡，这就要求物理学的发展必须超越标准模型。为此，味物理的主要目标是寻找CP破坏的新来源，并利用重味（含B或C夸克）粒子的衰变来精确测量标准模型参数。在魅力物理领域，一个特别有前途的现象是具有确定C和P本征值的粒子衰变为关联的DoDo对。DoDo系统中的相关性使得能够直接测量系统中的T（时间反演）对称性。由于在粲系统中已经观察到CP破坏，直接测量T对称性将允许测试CPT对称性，如果CPT对称性被打破，将明确指向标准模型之外的物理学。此外，这种关联的魅力对可以通过限制可能的共振来减少B介子衰变振幅分析的系统不确定性。这反过来又可以使我们更好地研究新类型强子的性质，如奇异介子和四夸克。LHCb实验是欧洲核子研究中心的四个主要探测器之一，为研究重味粒子进行了优化。探测器的独特能力提供了一个很好的平台，利用相关的粲强子来寻找新的物理。利用LHCb实验运行2和3期间收集的衰变样本，我将尝试在C=+1本征态中重建DoDo系统，并在DoDo不变质谱中提取相应的线形。这使得在随后的分析中确定其CP本征态的DoDo对的产率，并且是测量相关魅力系统中T违反的工具步骤。最终，这些相同的魅力系统也可以为美容系统中的CP违规提供关键约束。此外，我还将进行一项可行性研究，以量化的影响，包括相关的魅力对振幅分析使用蒙特-卡罗模拟样本的衰变。