Getting a flavour for New Physics with precision measurements of tree-level beauty decays

通过精确测量树级美丽衰减来体验新物理学

• 批准号: ST/R004536/3
• 负责人: Matthew Kenzie
• 金额: $ 7.65万
• 依托单位: University of Cambridge
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2023
• 资助国家: 英国
• 起止时间: 2023 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FR004536%2F3
• 关键词: Getting; flavour; New; Physics; precision

Elementary particle physics has an incredibly successful underlying theoretical framework known as the Standard Model which has produced a succession of successful predictions and subsequent discoveries in recent decades. This culminated in the discovery of the Higgs Boson in 2012, which was the last missing piece of the Standard Model. However, there are still a multitude of observed phenomena which the Standard Model cannot explain and the focus of this research is understanding the matter-antimatter asymmetry of the universe. In the hot early universe matter and antimatter should have been created in equal amounts; this is the simple conversion of energy into matter via Einstein's famous equation, E=mc^2. Once the universe cooled the matter and antimatter would have "annihlated" to leave behind an abundance of electromagnetic radiation. This electromagnetic radiation we see today as the cosmic microwave background, the static seen on an untuned televsion. However, there is clearly an imbalance as we also see large amounts of matter, which make up the stars, galaxies and ourselves whilst no antimatter is left at all. We can understand some part of this as being due to charge-parity symmetry (that which relates matter to antimatter) being broken. In the intial stages of matter-antimatter creation charge-parity violation results in a small excess of matter, which goes on to make up the observable universe of today, after the majority annihilates with the antimatter to leave behind the electromagnetic radiation still echoing around the universe. The problem is that the amount of charge-parity violation predicted by the theoretical framework underlying our understanding of elementary particle physics is nowhere near enough (a factor several billion off) to account for the observed matter to electromagnetic radiation ratio of the universe. This project uses data from the Large Hadron Collider to look for new fundamental physics particles which can help to explain the matter-antimatter discrepancy. By analysing millions of matter and antimatter decays produced at the LHCb experiment we can observe the subtle differences between them. The parameters we determine in this project are of particular interest because they can be measured completely independently of any input from the theoretical framework, i.e. independently of any prior knowledge. We can then use these parameters to prove the existence, and predict the behaviour, of new fundamental physics particles which explain why we live in a matter dominated universe and hence why we have atoms, molecules and life itself.

基本粒子物理学有一个非常成功的基础理论框架，称为标准模型，它在近几十年来产生了一系列成功的预测和随后的发现。2012年，希格斯玻色子的发现达到了顶峰，这是标准模型最后一个缺失的部分。然而，仍然有许多标准模型无法解释的观测现象，这项研究的重点是理解宇宙的物质-反物质不对称性。在炽热的早期宇宙中，物质和反物质应该以等量的方式被创造出来;这是通过爱因斯坦著名的方程E= mc ^2将能量简单地转化为物质。一旦宇宙冷却，物质和反物质就会“湮灭”，留下大量的电磁辐射。我们今天看到的这种电磁辐射就是宇宙微波背景辐射，即在未调谐的电视上看到的静电。然而，很明显存在着不平衡，因为我们也看到了大量的物质，它们构成了恒星、星系和我们自己，而没有反物质。我们可以理解这部分是由于电荷宇称对称性（将物质与反物质联系起来）被打破。在物质-反物质创生的初始阶段，电荷宇称破缺导致了物质的少量过剩，这就构成了今天的可观测宇宙，在大多数物质与反物质湮灭之后，留下的电磁辐射仍然在宇宙中回荡。问题是，我们对基本粒子物理学的理解所依据的理论框架所预测的电荷宇称破坏的数量远远不足以（相差数十亿倍）解释宇宙中观测到的物质与电磁辐射的比率。该项目使用大型强子对撞机的数据来寻找新的基本物理粒子，这些粒子可以帮助解释物质-反物质的差异。通过分析LHCb实验中产生的数百万个物质和反物质衰变，我们可以观察到它们之间的细微差异。我们在这个项目中确定的参数是特别感兴趣的，因为它们可以完全独立于理论框架的任何输入进行测量，即独立于任何先验知识。然后，我们可以使用这些参数来证明新的基本物理粒子的存在并预测其行为，这些粒子解释了为什么我们生活在物质主导的宇宙中，因此为什么我们有原子，分子和生命本身。