Applications of QCD in the Standard Model and Beyond

QCD 在标准模型及其他模型中的应用

• 批准号: SAPIN-2018-00031
• 负责人: Maltman, Kim
• 金额: $ 1.46万
• 依托单位: York University
• 依托单位国家: 加拿大
• 项目类别: Subatomic Physics Envelope - Individual
• 财政年份: 2019
• 资助国家: 加拿大
• 起止时间: 2019-01-01 至 2020-12-31
• 项目状态: 已结题
• 来源: https://www.nserc-crsng.gc.ca/ase-oro/Details-Detailles_eng.asp?id=677075
• 关键词: Applications; QCD; Standard; Model; Beyond

This grant proposal involves work aimed at elucidating the dynamics of the Standard Model of particle physics, both in the context of the Standard Model itself, and in the context of determinations of Standard Model contributions to processes currently under investigation as part of the intensive, ongoing experimental search for physics beyond the Standard Model either underway at present, or about to start, at major experimental facilities throughout the world. In these processes, a precision understanding of Standard Model contributions is crucial to the success of the very expensive experimental programs since these contributions serve as backgrounds which must be thoroughly and precisely understood if beyond-the-Standard-Model effects are to be identified. ******Of particular importance in this regard is the determination of the effects of the strong interactions, which, because of their strength (1) can be very numerically significant and (2) are amenable to treatment using a much more limited set of theoretical techniques than are effects produced by the weaker electromagnetic and weak interactions. Strong interaction effects will be evaluated using Quantum Chromodynamics (QCD), the theory of the strong (nuclear and sub-nuclear) interactions, employing a number of rigorous, well-established theoretical techniques, including large scale numerical simulations (lattice QCD). We will use these techniques, in combination with experimental data from various collider facilities, to make state-of-the-art determinations of Standard Model parameters such as the strength of the strong interaction coupling and the up-strange Cabibbo-Kobayashi-Maskawa matrix element, a parameter which describes how rapidly a hadronic state containing a strange quark can decay into states in which the strange quark has been converted into an up quark. A new determination of this latter quantity based on the strange hadronic decays of the heavy tau lepton is of particular interest in view of current indications of the possibility that the weak interactions couple with different strengths to the different leptons, a possibility that would provide unambiguous evidence for the presence of physics beyond the Standard Model. We will also continue previous work on looking for novel ("exotic") states of hadronic matter.******Part of the work involved in this proposal will also involve creating a suite of computer programs which will allow experimentalists at the new major Belle II facility in Japan to perform theoretical, QCD-based analyses of experimental data on hadronic decays of the tau lepton that will be generated as part of the multi-year program at the Belle II facility, expected to begin physics runs in 2018. The work in this grant proposal will thus also serve to increase the effectiveness of the collaboration between particle theorists and experimentalists.*****

这项资助提案涉及旨在阐明粒子物理标准模型动力学的工作，无论是在标准模型本身的背景下，还是在确定标准模型对当前正在研究的过程的贡献的背景下，作为目前正在或即将在世界各地的主要实验设施中正在进行的超出标准模型的物理实验的密集、持续的实验研究的一部分。在这些过程中，对标准模型贡献的精确理解对于非常昂贵的实验计划的成功至关重要，因为如果要识别超出标准模型的效应，则必须彻底而准确地理解这些贡献作为背景。 ******在这方面特别重要的是确定强相互作用的影响，由于其强度（1）可能在数值上非常显着，并且（2）与较弱的电磁和弱相互作用产生的影响相比，更适合使用更有限的一组理论技术进行处理。强相互作用效应将使用量子色动力学 (QCD) 进行评估，这是强（核和亚核）相互作用的理论，采用许多严格、完善的理论技术，包括大规模数值模拟（晶格 QCD）。我们将使用这些技术，结合来自各种对撞机设施的实验数据，对标准模型参数进行最先进的确定，例如强相互作用耦合的强度和上奇异卡比博-小林-益川矩阵元素，该参数描述了包含奇异夸克的强子态衰变成奇异夸克已转换为上夸克的状态的速度。鉴于目前的迹象表明弱相互作用与不同轻子的不同强度耦合的可能性，基于重 tau 轻子的奇怪强子衰变对后一个量的新确定特别令人感兴趣，这种可能性将为标准模型之外的物理存在提供明确的证据。我们还将继续之前的工作，寻找新的（“奇异”）强子物质状态。********该提案涉及的部分工作还将涉及创建一套计算机程序，该程序将允许日本新的主要 Belle II 设施的实验人员对 tau 轻子强子衰变的实验数据进行基于 QCD 的理论分析，这些数据将作为 Belle II 设施多年计划的一部分生成，预计将于 物理学将于 2018 年运行。因此，这项资助提案中的工作也将有助于提高粒子理论家和实验家之间合作的有效性。*****