Standard Model Phenomenolgy.

标准模型现象学。

• 批准号: ST/T000856/1
• 负责人: Robert Thorne
• 金额: $ 46.68万
• 依托单位: University College London
• 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: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FT000856%2F1
• 关键词: Standard; Model; Phenomenolgy.

Keith Hamilton's research concerns the development of high precision Monte Carlo simulations of collider Physics processes. These facilitate discovery and interpretation of new physics at the Large Hadron Collider (LHC). While precision simulations may not be needed to claim a discovery, e.g. if new physics appears as a clear `bump' in a smooth distribution, (as did the Higgs boson), in many scenarios, such as supersymmetry, signals are expected to manifest as subtle distortions in the shapes of distributions. An accurate understanding of the Standard Model background, subject to all experimental cuts, is then unavoidable for claiming a discovery, or setting exclusion limits. Precision simulations are also essential to determine what it is that has been found. The recently discovered 125 GeV mass Higgs boson is the prime example of this. In 2012-2013 Hamilton and collaborators in Milan and Oxford developed the world's most accurate simulation of Higgs boson production. This simulation is now used by default by the ATLAS and CMS collaborations, appearing in their publications confronted with measurements to probe Higgs boson properties. In recent years Hamilton's work has shown how to extend the methodology behind that cutting-edge simulation to an important wider range of LHC reactions. In the coming years Hamilton will work as part of a new team, comprising three other world-class researchers, to extend the most central, parton shower, component of general purpose Monte Carlo event generators -- the most widely used theoretical tools in particle physics. General purpose event generators are at the heart of the way in which collider physics is carried out, impacting on the whole community. Thorne's work is complementary to that of Hamilton. It involves the precise details of the initial state appearing in hadronic particle collisions. At hadron colliders, e.g. the Large Hadron Collider (LHC), the particle beam is effectively made up of the fundamental particles inside the proton - quarks and gluons, generically known as partons. Predictions for Standard Model processes, and potentially those of new physics, require the precise partonic composition of the hadrons in terms of both the energy scale of the scattering process (e.g., the mass of a particle produced) and the momentum fraction of the incoming proton carried by the parton. Thorne is the lead member of an established PDF group that provides one of sets of parton distribution functions (PDFs) used as standard by both the experimental and theoretical analyses at the LHC and other high energy particle physics experiments. The approach is continually refined, both in terms of theoretical sophistication, and by inclusion of data which become available and due to increased precision or different sensitivity to PDFs, lead to further PDF constraints. Thorne's work will lead to improved PDF determination, providing updated PDFs for universal use, and he will also investigate the consequences of any changes. This will lead to a better understanding of current and upcoming measurements, and will also influence planning for future high energy particle physics experiments. Additionally, Thorne is a core member of the PDF4LHC working group (a member of the steering committee since the inception, and one of the main drivers and organisers) which provides recommendations for use of PDF sets at the LHC and acts as a direct liason to the LHC experimental community.Both Hamilton and Thorne are involved in ever increasing precision for calculations at the LHC, which is particularly essential in order maximise the potential of the LHC, particularly given the current situation of no clear signals of new physics, but continual appearance of unprecedented variety and precision of Standard Model tests. Both will provide expertise in interpretingany deviations which could be the first sign of Beyond the Standard Model (BSM) Physics.

基思·汉密尔顿的研究涉及对撞机物理过程的高精度蒙特卡罗模拟的发展。这些有助于在大型强子对撞机(LHC)上发现和解释新的物理。虽然可能不需要精确的模拟来宣称一个发现，例如，如果新的物理看起来像是光滑分布中的一个明显的“凹凸”(就像希格斯玻色子一样)，但在许多情况下，例如超对称，信号预计会表现为分布形状的微妙扭曲。因此，对于标准模型背景的准确理解，受到所有试验性削减的限制，对于声称一项发现或设定排除限制是不可避免的。精确的模拟对于确定发现了什么也是至关重要的。最近发现的125GeV质量希格斯玻色子就是最好的例子。2012-2013年间，汉密尔顿及其在米兰和牛津的合作者开发了世界上最精确的希格斯玻色子产生模拟。这种模拟现在被ATLAS和CMS的合作默认使用，出现在他们的出版物中，面临着探测希格斯玻色子性质的测量。近年来，汉密尔顿的工作展示了如何将尖端模拟背后的方法扩展到重要的更广泛的大型强子对撞机反应。在接下来的几年里，汉密尔顿将作为一个新团队的一部分进行工作，该团队包括另外三名世界级的研究人员，以扩展通用蒙特卡罗事件发生器中最核心的部分，即部分子簇射，而蒙特卡罗事件发生器是粒子物理学中使用最广泛的理论工具。通用事件发生器是对撞机物理实现方式的核心，对整个社区都有影响。索恩的工作是对汉密尔顿的补充。它涉及强子粒子碰撞中出现的初始状态的精确细节。在强子对撞机上，例如大型强子对撞机(LHC)，粒子束实际上是由质子内部的基本粒子-夸克和胶子，通常被称为部分子。对标准模型过程的预测，以及潜在的新物理过程的预测，都需要强子在散射过程的能量标度(例如，产生的粒子的质量)和由部分子携带的入射质子的动量分数方面的精确的部分子组成。索恩是一个已建立的PDF小组的主要成员，该小组提供一组部分子分布函数(PDF)，作为大型强子对撞机和其他高能粒子物理实验的实验和理论分析的标准。该方法不断改进，无论是在理论上的复杂性，还是通过纳入可用的数据，以及由于提高了精度或对PDF的不同敏感性，导致了进一步的PDF限制。索恩的工作将导致改进PDF确定，提供更新的PDF供普遍使用，他还将调查任何更改的后果。这将有助于更好地了解当前和即将进行的测量，并将影响未来高能粒子物理实验的规划。此外，索恩是PDF4LHC工作组的核心成员(从一开始就是指导委员会的成员，也是主要的推动者和组织者之一)，该工作组为大型强子对撞机提供使用PDF集的建议，并直接与大型强子对撞机实验社区联系。汉密尔顿和索恩都参与了大型强子对撞机计算精度的不断提高，这对于最大限度地发挥大型强子对撞机的潜力尤其重要，特别是考虑到目前没有新的物理信号，但标准模型测试不断出现前所未有的多样性和精确度。这两家公司都将提供解释任何偏差的专业知识，这些偏差可能是超越标准模型(BSM)物理的第一个迹象。

项目成果

Publishing statistical models: Getting the most out of particle physics experiments

• DOI: 10.21468/scipostphys.12.1.037
• 发表时间: 2021-09
• 期刊: SciPost Physics
• 影响因子: 5.5
• 作者: K. Cranmer;S. Kraml;H. Prosper;P. Bechtle;F. Bernlochner;I. Bloch;E. Canonero;M. Chrzaszcz

The PDF4LHC21 combination of global PDF fits for the LHC Run III*

• DOI: 10.1088/1361-6471/ac7216
• 发表时间: 2022-08-01
• 期刊: JOURNAL OF PHYSICS G-NUCLEAR AND PARTICLE PHYSICS
• 影响因子: 3.5
• 作者: Ball, Richard D.;Butterworth, Jon;Yuan, C-P
• 通讯作者: Yuan, C-P

Snowmass 2021 Whitepaper: Proton Structure at the Precision Frontier

Snowmass 2021 白皮书：精密前沿的质子结构

• DOI: 10.5506/aphyspolb.53.12-a1
• 发表时间: 2022
• 期刊: Acta Physica Polonica B
• 影响因子: 0.5
• 作者: Amoroso, S.;Apyan, A.;Armesto, N.;Ball, R.D.;Bertone, V.;Bissolotti, C.;Blümlein, J.;Boughezal, R.;Bozzi, G.;Britzger, D.
• 通讯作者: Britzger, D.

Precise predictions for boosted Higgs production

精确预测希格斯粒子产量的增加

• DOI: 10.48550/arxiv.2005.07762
• 发表时间: 2020
• 期刊: arXiv e-prints
• 作者: Becker K.

Parton distributions from LHC, HERA, Tevatron and fixed target data: MSHT20 PDFs

• DOI: 10.1140/epjc/s10052-021-09057-0
• 发表时间: 2021-04-01
• 期刊: EUROPEAN PHYSICAL JOURNAL C
• 影响因子: 4.4
• 作者: Bailey, S.;Cridge, T.;Thorne, R. S.
• 通讯作者: Thorne, R. S.