The Flavour Anomalies: Fluke, Fallacy or New Physics?

风味异常：侥幸、谬论还是新物理学？

• 批准号: 2310073
• 负责人: Eluned Smith
• 金额: $ 54万
• 依托单位: Massachusetts Institute of Technology
• 依托单位国家: 美国
• 项目类别: Standard Grant
• 财政年份: 2023
• 资助国家: 美国
• 起止时间: 2023-09-01 至 2026-08-31
• 项目状态: 未结题
• 来源: https://www.nsf.gov/awardsearch/showAward?AWD_ID=2310073&HistoricalAwards=false
• 关键词: Flavour; Anomalies; Fluke; Fallacy; New

The Standard Model of particle physics represents our best current knowledge of the fundamental particles that make up our universe and the interactions (forces) that govern them. Although to date most fundamental particles have been observed to behave as predicted by the Standard Model, cosmological observations tell us that the Standard Model cannot be the complete picture. For example, in the Standard Model, matter and anti-matter are a near-perfect mirror of each other. However, the dominance of matter in our universe tells us that there must be some, as of yet unknown, interaction breaking this matter, anti-matter symmetry. The LHCb experiment is one of the four experiments situated on the Large Hadron Collider (LHC) at CERN. It is designed to make precision measurements of a particle called a beauty (b) quark. This award focuses on the study of b-quark decays which are very suppressed in the Standard Model. By precisely measuring the rates at which these rare processes happen, we can infer the existence of new interactions, not described within the Standard Model. Over recent years, measurements of these rare b decays have shown deviations with Standard Model predictions. This award will further our understanding behind what is causing these anomalies, with the goal of determining whether their origin could be the first sign of a beyond-the-Standard-Model process at the LHC. The PI of this project is the founder of the Laura Bassi initiative within the LHCb collaboration, which brings together early career researchers interested in tackling issues of gender and diversity within particle physics. This grant will support the PI’s continued work in this area.Whereas the tensions observed in rare b-decays can be over 5 standard deviations with respect to the Standard Model, these deviations could be due to poor theoretical descriptions of non-local hadronic effects, which cannot be derived from first principles in the Standard Model. This award performs a novel data-driven measurement of non-local hadronic effects in the decay B^0→K^(*0) μ+μ-, providing a crucial part of the flavour-anomaly puzzle. Similar methods are used to measure non-local tauonic contributions to B^0→K^(*0) μ^+ μ^-, via the decay B^0→K^(*0) [τ^+ τ^-→μ^+μ- ]. The expected sensitivity on B(B^0→K^(*0) τ^+ τ^- ) obtained using this method is world-leading. Measurements of b→sτ^+ τ^- are critical to understanding the anomalies, as favored new physics explanations predict large enhancements in theses modes. This project will also perform the first fit for the imaginary contributions to the underlying effective couplings in B^0→K^(*0) μ+μ- , with the proposed method resulting in an order-of-magnitude improvement on CP-violation constraints in b→sl+l- decays. This measurement is interesting in light of the flavor anomalies, and because constraints on beyond-the-SM CP violation are central to understanding the dominance of matter over anti-matter in the universe. This project will also commission and validate the performance of the LHCb Upgrade I detector, which takes data during the LHC Run 3 (2022-2026) for the first time. This commissioning work will be the cornerstone of subsequent measurements of b→sμ^+ μ^-processes using Run 3 data, which are also performed as part of this project.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.

粒子物理学的标准模型代表了我们对构成我们宇宙的基本粒子以及支配它们的相互作用（力）的最佳当前知识。尽管迄今为止，已经观察到大多数基本粒子的行为是按照标准模型预测的，但宇宙学的观察告诉我们，标准模型不能是完整的图片。例如，在标准模型中，物质和反物质是彼此接近完美的镜子。但是，物质在我们的宇宙中的主导地位告诉我们，既然尚不清楚，互动打破了这一问题，反物质对称性。 LHCB实验是位于CERN大型强子对撞机（LHC）上的四个实验之一。它旨在对称为美（b）夸克的粒子进行精确测量。该奖项的重点是对标准模型中非常受到压制的B Quark衰减的研究。通过精确衡量这些罕见过程发生的速率，我们可以推断出在标准模型中未描述的新相互作用的存在。近年来，这些罕见的B衰变的测量显示出具有标准模型预测的偏差。该奖项将进一步在引起这些异常的原因之后我们的理解，目的是确定其起源是否可能是LHC超出标准模型过程的第一个迹象。该项目的PI是LHCB合作中的Laura Bassi倡议的创始人，该计划汇集了有兴趣解决粒子物理学中性别和多样性问题的早期职业研究人员。这笔赠款将支持PI在这一领域的继续工作。在罕见的b-decase中观察到的紧张关系可能超过5个标准模型的标准偏差，这些偏差可能是由于对非本地性强化效应的理论描述不佳，因此该奖项对非局部数据驱动的exay decay decay decay bel b^0 cr+cr y+++^0→*0•（*）（*0要求）进行了新的数据驱动的测量。风味 - 异常难题的一部分。通过类似的方法，通过衰减B^0→K^（*0）[τ^+τ^ - →μ^+μ-]测量对B^0→K^（*0）μ^+μ^ - 的非本地陶器贡献。使用此方法获得的B（B^0→K^（*0）τ^+τ^ - ）的预期灵敏度是世界领先的。 B→Sτ^+τ^的测量对于理解异常至关重要，因为普通的新物理解释预测了这些模式中的大量增强。该项目还将对B^0→K^（*0）μ+μ-的基础有效耦合的假想贡献进行首次拟合，并使用提出的方法对B→SL+L-衰减中的CP-Violation约束进行了提出的改善。鉴于风味异常，这种测量很有趣，并且由于违规超越SM CP的限制对于理解物质在宇宙中的抗肌的主导地位至关重要。该项目还将委托和验证LHCB升级I检测器的性能，该探测器首次在LHC运行3（2022-2026）期间进行数据。这项调试工作将是随后使用运行3个数据对B→Sμ^+μ^ - 程序进行测量的基石，这些数据也是该项目的一部分。该奖项反映了NSF的法定任务，并被认为是通过基金会的知识分子优点和更广泛影响的审查审查的审查标准来通过评估来诚实的支持。