Searching for Physics Beyond the Standard Model

寻找标准模型之外的物理学

• 批准号: SAPIN-2019-00026
• 负责人: London, David
• 金额: $ 5.1万
• 依托单位: Université de Montréal
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2021
• 资助国家: 加拿大
• 起止时间: 2021-01-01 至 2022-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=739408
• 关键词: Searching; Physics; Beyond; Standard; Model

The ultimate goal of particle physics is to find the fundamental theory of "unification" that describes all the particles of the universe, and the forces with which they interact, in a simple and elegant way. A first step was made with the development of the Standard Model (SM), which explains essentially all experimental data to date. However, for many reasons, we believe that the SM cannot be the whole story -- there must be physics beyond the SM. The search for this new physics (NP) is the crucial problem in particle physics today. I have been involved in this endeavour for most of my career, and my proposed research program continues along these lines: to participate in the search for new physics. The Large Hadron Collider (LHC) at the particle-physics laboratory CERN (Geneva, Switzerland) has four experiments that are looking for signs of NP. While no direct signals of NP have been seen, i.e., no new, non-SM particles have been detected, one of the experiments, LHCb, has observed and confirmed several indirect hints of NP. That is, there are measurements of observables that disagree with the predictions of the SM, suggesting that there are virtual NP contributions to the processes. These indirect signals point to two different decays of the b quark in which NP might be present. There is also a longstanding anomaly in another observable, the muon anomalous magnetic moment. Finally, 27% of the energy of the universe is made up of dark matter (DM), i.e., new particles that interact only gravitationally. As the SM does not contain any DM candidates, the existence of DM is already proof of NP. The bottom line is that, at present, we have several experimental results suggesting where to look for the physics beyond the SM. In searching for NP, (i) we want to confirm that the experimental data does indeed provide clear evidence for NP, and (ii) if present, we want to identify the NP. To this end, it is necessary to propose NP explanations of the experimental results and suggest ways of differentiating competing explanations. It is also important to find new ways of searching for signals of NP. My research involves all of these approaches. Now, research in particle physics is purely curiosity-driven - we simply want to understand how the universe works. Knowing what the NP is will help in this regard, but will not lead directly to improvements for society. On the other hand, historically there have always been numerous technological advances related to the building of the colliders and detectors used to search for NP. The most famous of these is the World Wide Web, which was invented at CERN in the 1980s, and has led to the internet. There is also the training of highly-qualified personnel (HQP). Research in particle physics develops a set of problem-solving skills that can be applied in many other areas. For example, I know of HQP who are now working in teaching, computer science, finance, geography, forestry, oceanography, and medical imaging.

粒子物理学的最终目标是找到“统一”的基本理论，以简单而优雅的方式描述宇宙中的所有粒子以及它们相互作用的力。第一步是发展标准模型（SM），它基本上解释了迄今为止所有的实验数据。然而，由于许多原因，我们认为SM不能是故事的全部-必须有超越SM的物理学。寻找这种新的物理学（NP）是当今粒子物理学的关键问题。在我职业生涯的大部分时间里，我一直在从事这方面的工作，我提出的研究计划也沿着这些路线继续下去：参与寻找新的物理学。位于粒子物理实验室CERN（瑞士日内瓦）的大型强子对撞机（LHC）有四个实验正在寻找NP的迹象。虽然没有看到NP的直接信号，即，没有发现新的非SM粒子，其中一个实验LHCb已经观察到并证实了NP的几个间接暗示。也就是说，存在与SM的预测不一致的可观测量的测量，这表明存在虚拟NP对过程的贡献。这些间接的信号指出了B夸克可能存在NP的两种不同衰变。在另一个观测到的μ子异常磁矩中也存在长期的异常。最后，宇宙能量的27%是由暗物质（DM）组成的，即，新的粒子只通过引力相互作用。由于SM不包含任何DM候选，DM的存在已经是NP的证明。底线是，目前，我们有几个实验结果表明在哪里寻找SM之外的物理。在寻找NP的过程中，（i）我们希望确认实验数据确实为NP提供了明确的证据，（ii）如果存在，我们希望识别NP。为此，有必要提出实验结果的NP解释，并提出区分竞争性解释的方法。寻找寻找NP信号的新方法也很重要。我的研究涉及所有这些方法。现在，粒子物理学的研究纯粹是好奇心驱动的-我们只是想了解宇宙是如何运作的。了解NP是什么将在这方面有所帮助，但不会直接导致社会的改善。另一方面，历史上一直有许多与建造用于搜索NP的对撞机和探测器有关的技术进步。其中最著名的是万维网，它是在20世纪80年代由欧洲核子研究中心发明的，并导致了互联网。此外，还有高素质人员（HQP）培训。粒子物理学的研究开发了一套解决问题的技能，可以应用于许多其他领域。例如，我知道HQP现在从事教学，计算机科学，金融，地理，林业，海洋学和医学成像。