Phenomenology from lattice QCD and collider physics

晶格 QCD 和对撞机物理的现象学

• 批准号: ST/T000945/1
• 负责人: Christine Davies
• 金额: $ 93.56万
• 依托单位: University of Glasgow
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2020
• 资助国家: 英国
• 起止时间: 2020 至 无数据
• 项目状态: 未结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FT000945%2F1
• 关键词: Phenomenology; lattice; QCD; collider; physics

The Glasgow theory group has a strong reputation in studies of the subatomic world, innovating to extend our understanding of how it works. This is aimed at uncovering the fundamental constituents of matter and the nature of the interactions that operate between them. There are two approaches to this, and we will use both of them. One is to perform very accurate calculations within the theoretical framework of the Standard Model that we believe correctly describes the particles that we have seen so far and the strong, weak and electromagnetic forces of Nature. Discrepancies between these accurate calculations and what is seen in experiments will then point the way to a deeper theory that describes fundamental particle physics more completely. The second method is concerned with what we might see at CERN's Large Hadron Collider if one of the suggested deeper theories is correct. We must make sure that we optimise the analysis of the experiments there to learn as much as possible. Accurate calculations in the Standard Model have foundered in the past on the difficult problem of how to handle the strong force. This force is important inside particles that make up the atomic nucleus, the proton and neutron and a host of similar particles called hadrons produced in high energy collisions. The constituents of these particles are quarks, and they are trapped inside hadrons by the behaviour of the strong force. This 'confinement' of quarks makes calculations of the effect of the strong force on the physics of hadrons very challenging. It can be tackled, however, using the numerical technique of lattice QCD, which Glasgow has been instrumental in turning into a precision tool, and where we continue to lead progress. Here we will predict more accurately how hadrons containing b quarks decay via the weak force and we will reduce uncertainties on how neutrinos interact with protons and neutrons in the atomic nucleus. We will also improve accuracy on the tiny effect of the strong force on the magnetic moment of the muon. These calculations are aimed at improving analysis of experiments around the world (including at CERN), which aim to understand the violations of symmetry between matter and antimatter, how neutrinos behave and whether the value of the muon's magnetic moment reveals the presence of new particles. The Glasgow team will also investigate theories that go beyond the Standard Model and confront them with LHC data. The recent discovery of the Higgs boson was the final piece of the Standard Model and is a triumph for both theoretical and experimental particle physics. However, there is strong evidence that the Standard Model needs to be embedded in a more fundamental theory of nature as there is no explanation for the over-abundance of matter compared to anti-matter or the presence of dark matter, both of which are firmly established by astrophysical observations. Theoretical insights suggest that the Higgs boson could be the harbinger of a more fundamental theory that will address these questions. New physics would then manifest itself in deviations of the Higgs boson's properties from the Standard Model expectation. We will undertake a comprehensive programme to determine its properties in the most accurate way by developing computer-based strategies that will reveal sensitivity where the traditional methods of the past are bound to fail. In parallel, we will also investigate the properties of the top quark, which are complementary tell-tale signs of new physics. We will compare our findings to new physics models like theories of Grand Unification, which unify the three forces to one single force while addressing the aforementioned shortcomings of the Standard model at the same time. We will determine if these exciting theories are consistent with LHC measurements and determine which steps to take next to uncover the fundamental truths of the universe.

格拉斯哥理论小组在亚原子世界的研究方面享有很高的声誉，他们不断创新，扩展了我们对亚原子世界如何运作的理解。这是为了揭示物质的基本成分和它们之间相互作用的本质。有两种方法，我们将使用这两种方法。一个是在标准模型的理论框架内进行非常精确的计算，我们相信标准模型正确地描述了我们迄今为止所看到的粒子以及自然界的强、弱和电磁力。这些精确的计算结果与实验结果之间的差异将为更全面地描述基本粒子物理学的更深层次的理论指明道路。第二种方法与我们在欧洲核子研究中心的大型强子对撞机上可能看到的东西有关，如果建议的更深层次的理论之一是正确的。我们必须确保优化实验分析，尽可能多地学习。在过去，标准模型中的精确计算在如何处理强作用力的难题上失败了。这种力在组成原子核、质子和中子的粒子以及在高能碰撞中产生的大量被称为强子的类似粒子中很重要。这些粒子的成分是夸克，它们被强力的作用困在强子里。夸克的这种“约束”使得强子物理中强作用力的计算非常具有挑战性。然而，可以使用晶格QCD的数值技术来解决这个问题，格拉斯哥在将其转变为精密工具方面发挥了重要作用，并且我们将继续引领进步。在这里，我们将更准确地预测含有b夸克的强子如何通过弱力衰变，我们将减少中微子如何与原子核中的质子和中子相互作用的不确定性。我们还将提高强作用力对μ子磁矩的微小影响的准确性。这些计算旨在改善世界各地（包括欧洲核子研究中心）的实验分析，这些实验旨在了解物质和反物质之间对称性的破坏，中微子的行为以及μ子磁矩的值是否揭示了新粒子的存在。格拉斯哥的研究小组还将研究超越标准模型的理论，并用大型强子对撞机的数据来对抗它们。最近发现的希格斯玻色子是标准模型的最后一块，是理论和实验粒子物理学的一次胜利。然而，有强有力的证据表明，标准模型需要嵌入到一个更基本的自然理论中，因为没有解释与反物质相比物质过多或暗物质存在的原因，这两者都是由天体物理学观测所确定的。理论上的见解表明，希格斯玻色子可能预示着一种更基本的理论将解决这些问题。然后，新的物理学将在希格斯玻色子的性质与标准模型预期的偏差中表现出来。我们将执行一项全面的方案，以最准确的方式确定其性质，制定以计算机为基础的战略，揭示过去传统方法注定失败的敏感性。与此同时，我们还将研究顶夸克的性质，这是新物理学的补充迹象。我们将把我们的发现与新的物理模型，如大统一理论进行比较，大统一理论将三种力统一为一种力，同时解决了上述标准模型的缺点。我们将确定这些令人兴奋的理论是否与大型强子对撞机的测量结果一致，并确定下一步要采取哪些步骤来揭示宇宙的基本真理。

项目成果

Quartic Gauge-Higgs couplings: constraints and future directions

• DOI: 10.1007/jhep10(2022)172
• 发表时间: 2022-08
• 期刊: Journal of High Energy Physics
• 影响因子: 5.4
• 作者: Anisha;Oliver Atkinson;Akanksha Bhardwaj;C. Englert;Panagiotis Stylianou

Higgs Footprints of Hefty ALPs

巨大 ALP 的希格斯足迹

• DOI: 10.3204/pubdb-2023-04097
• 发表时间: 2023
• 作者: Anisha

Higgs boson footprints of hefty ALPs

巨大 ALP 的希格斯玻色子足迹

• DOI: 10.1103/physrevd.108.095032
• 发表时间: 2023
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Anisha

Extended Higgs sectors, effective field theory and Higgs phenomenology

扩展希格斯扇区、有效场论和希格斯现象学

• DOI: 10.48550/arxiv.2103.01810
• 发表时间: 2021
• 作者: Anisha

BSM reach of four-top production at the LHC

• DOI: 10.1103/physrevd.108.035001
• 发表时间: 2023-08
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Anisha;Oliver Atkinson;Akanksha Bhardwaj;Christoph Englert;Wrishik Naskar;Panagiotis Stylianou