Finding true LUV

寻找真正的 LUV

• 批准号: ST/T005076/1
• 负责人: Lucia Grillo
• 金额: $ 68.51万
• 依托单位: University of Manchester
• 依托单位国家: 英国
• 项目类别: Fellowship
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FT005076%2F1
• 关键词: Finding; true; LUV

Over the last few decades, the Standard Model (SM) of particle physics, which describes our current knowledge of nature at fundamental scales, has been probed by a broad variety of experiments, and it has successfully predicted, and/or explained most of the physical phenomena observed so far. A notable verification of the power of the SM was the discovery in 2012 of its final piece, the Higgs boson. However, as Isaac Asmiov famously said, "The most exciting phrase to hear in science, the one that heralds new discoveries, is not 'Eureka!' but 'that's funny!'", and luckily there are still "funny" phenomena, which are not completely understood in our theoretical description, and are the subjects of today's searches for new particles and forces. In our current understanding, matter consists of twelve fundamental particles: the six quarks (u, d, s, c, b, t ordered by increasing mass), and six leptons, including the electron with its heavier partners, the muon and the tau, and their three associated neutrinos.Just as the neutrinos have surprised us in the last decades, the charged leptons (electron, muon, tau) are also important to investigate. We expect the charged leptons to have identical properties, besides their mass, and to be produced with the same probability by the same processes (Lepton Universality). Instead, the most recent experimental results hint at a breaking of this principle (Lepton Universality Violation - LUV). The goal of my proposal is to shed some light on these anomalies: to confirm or disprove the effect and investigate which type of processes beyond our current theoretical description are responsible for such "funny" observations.The most precise tests of lepton universality compare b-hadrons, bound states of quarks, containing at least a quark (or antiquark) of b-type decaying into particles including different charged leptons and neutrinos. I will measure the difference in the abundance of these decays in nature with high precision, in order to establish if lepton universality is violated or not. In addition, I will measure different quantities to better understand the processes responsible for these b-hadrons decays, identifying the nature of possible new physics phenomena.I will use samples of millions of b-hadron decays collected with the LHCb experiment at the Large Hadron Collider (LHC). The LHC, located 100m underground just outside Geneva, collides protons at energies that have never previously been reached in a laboratory on Earth and the LHCb experiment is currently the best apparatus to measure b-hadron properties. To ensure ultimate precision in these measurements, I will propose a tracking system design for future LHCb upgrades during the High-Luminosity LHC phase (2026-2038).I will face several significant challenges, including the exploration of new strategies to analyse huge data samples, development of efficient software using the latest computing technologies, and design of new detectors using emerging technologies. By addressing these challenges, my proposal generates an impact in science and industry beyond the immediate scientific scope of the project.

在过去的几十年里，粒子物理学的标准模型（SM）描述了我们目前在基本尺度上对自然的认识，已经通过各种各样的实验进行了探索，并且成功地预测和/或解释了迄今为止观察到的大多数物理现象。SM的力量的一个值得注意的验证是在2012年发现了它的最后一个部分，希格斯玻色子。但是，正如艾萨克·阿斯米洛夫的名言所说：“在科学中听到的最令人兴奋的短语，预示着新发现的短语，不是'尤里卡！“但是"真有趣！幸运的是，仍然有一些“有趣”的现象，在我们的理论描述中还没有完全理解，并且是今天寻找新粒子和力的主题。在我们目前的理解中，物质由12种基本粒子组成：6种夸克（u、d、s、c、B、t，按质量递增顺序排列）和6种轻子，包括电子和它的较重伙伴μ子、τ子，以及它们的3个相关中微子。正如中微子在过去几十年里让我们感到惊讶一样，带电轻子（电子、μ子、τ子）也是研究的重要对象。我们期望带电轻子除了质量之外，还具有相同的性质，并且通过相同的过程以相同的概率产生（轻子普适性）。相反，最近的实验结果暗示了这一原则的突破（轻子普适性破坏- LUV）。我的建议的目的是阐明这些异常现象：证实或反驳这种效应，并调查超出我们目前理论描述的哪种类型的过程是造成这种“有趣”的观察结果的原因。轻子普适性的最精确测试比较b-强子，夸克的束缚态，至少包含一个b型夸克（或反夸克），衰变成包括不同带电轻子和中微子的粒子。我将以高精度测量自然界中这些衰变丰度的差异，以确定轻子普适性是否被破坏。此外，我将测量不同的量，以更好地了解这些b-强子衰变的过程，识别可能的新物理现象的性质。我将使用大型强子对撞机（LHC）的LHCb实验收集的数百万个b-强子衰变的样本。大型强子对撞机位于日内瓦郊外地下100米处，以地球实验室从未达到的能量碰撞质子，LHCb实验是目前测量b-强子性质的最佳设备。为了确保这些测量的最终精度，我将提出一个跟踪系统设计，用于未来LHCb在高亮度LHC阶段（2026-2038年）的升级。我将面临几个重大挑战，包括探索新的策略来分析巨大的数据样本，使用最新的计算技术开发高效的软件，以及使用新兴技术设计新的探测器。通过应对这些挑战，我的建议对科学和工业产生的影响超出了项目的直接科学范围。