Particle Physics Consolidated Grant from the University of Sheffield: Energy Frontier, Neutrinos, Dark Matter

谢菲尔德大学粒子物理学综合资助：能源前沿、中微子、暗物质

• 批准号: ST/S000747/1
• 负责人: Davide Costanzo
• 金额: $ 309.32万
• 依托单位: University of Sheffield
• 依托单位国家: 英国
• 项目类别: Research Grant
• 财政年份: 2019
• 资助国家: 英国
• 起止时间: 2019 至 无数据
• 项目状态: 已结题
• 来源: https://gtr.ukri.org/projects?ref=ST%2FS000747%2F1
• 关键词: Particle; Physics; Consolidated; Grant; University

"What is the Universe made of, and why?" Sheffield's HEP programme aims to address this fundamental question. There are two problems here: about 5/6 of the matter in the Universe seems to be an as yet undiscovered particle (dark matter), and the remaining 1/6 is all matter - not the 50:50 matter-antimatter mix we make in laboratories.We search for the dark matter particle in two ways: at the energy frontier, by seeking to detect new particles created by the high-energy proton-proton collisions of the LHC at CERN, and in direct searches, attempting to observe these particles in the Galaxy itself. The theory of supersymmetry, which predicts a whole set of particles related to, but more massive than, the known particles of the Standard Model (SM), offers a candidate dark matter particle. If supersymmetric particles can be made at the LHC, they should be detected in ATLAS. Our programme searches specifically for new Higgs bosons and for particles related to the SM quarks and gluons. At ATLAS, we also study SM processes involving the force carriers of the weak interaction, probing our understanding of the SM. Looking to the future, we are contributing essential work to the upgrade of the ATLAS experiment required to take full advantage of higher event rates in future running of the LHC.Most of the matter in our Galaxy is dark matter. In the LZ experiment, we search for evidence of dark matter colliding with Xe atoms in the experiment and causing them to recoil. This experiment will be the most sensitive dark matter detector ever constructed. Understanding possible background - non-dark-matter - events is critical to this, and we have world leading expertise in this field. In addition, we are leading the development of directional dark matter detectors, which will be vital in proving that any candidate signal really does come from the Galaxy and not the Earth. We are also the only UK group involved in the search for axions: another possible type of dark matter particle which cannot be detected at the LHC or in standard dark matter experiments.Why is the matter in the Universe all matter, not antimatter? The answer to this question must lie in subtle differences between particles and antiparticles, an effect called CP violation. The CP violating effects so far observed are not nearly large enough to create the Universe we see. The most likely source for more CP violation is in the interactions of neutrinos. A key observation is that neutrinos have mass, and that different types of neutrinos can interchange their identities in flight. The T2K experiment has made measurements of this, and has detected tantalising hints of CP violation. We plan to build on this work, both in running experiments (T2K and SBND) and in designing the next generation of neutrino experiments which will have much greater sensitivity. We have developed tools to assist the neutrino community in comparing results and improving our understanding of how neutrinos interact. Our access to Boulby Mine provides an invaluable low-background laboratory for testing materials and detector prototypes.Last but not least, we seek to apply HEP technology to industry and to solving global problems. We are using techniques developed for ATLAS to contribute to the development of robotics and to deal with highly radioactive environments such as Chernobyl. We are designing muon detectors to search for nuclear contraband and monitor volcanoes. Our signal processing techniques are being applied to improving medical imaging for heart patients. Our expertise in water Cherenkov neutrino detection is being exploited in an experiment designed to monitor compliance with nuclear non-proliferation treaties. All of this work builds on our STFC core programme to benefit the wider world.

“宇宙是由什么组成的，为什么？“谢菲尔德的HEP计划旨在解决这个根本问题。这里有两个问题：宇宙中大约五分之六的物质似乎是一种尚未被发现的粒子。剩下的1/6都是物质--而不是我们在实验室里制造的50：50的物质-反物质混合物。我们通过两种方式寻找暗物质粒子：在能源前沿，通过寻求探测由欧洲核子研究中心的大型强子对撞机的高能质子-质子碰撞产生的新粒子，以及直接搜索，试图在银河系中观察这些粒子。超对称理论预言了一整套与标准模型（SM）中已知粒子相关但质量更大的粒子，这提供了一个候选的暗物质粒子。如果超对称粒子可以在大型强子对撞机上制造出来，它们应该可以在ATLAS上被检测到。我们的计划专门寻找新的希格斯玻色子和与SM夸克和胶子有关的粒子。在ATLAS，我们还研究了涉及弱相互作用的力载体的SM过程，探索我们对SM的理解。展望未来，我们正在为ATLAS实验的升级做出重要的贡献，以便在LHC未来的运行中充分利用更高的事件率。我们银河系中的大部分物质是暗物质。在LZ实验中，我们寻找暗物质在实验中与氘原子碰撞并导致它们反冲的证据。这个实验将是有史以来最灵敏的暗物质探测器。了解可能的背景-非暗物质-事件对此至关重要，我们在这一领域拥有世界领先的专业知识。此外，我们正在领导定向暗物质探测器的开发，这对于证明任何候选信号确实来自银河系而不是地球至关重要。我们也是唯一一个参与寻找轴子的英国小组：另一种可能的暗物质粒子，在LHC或标准暗物质实验中无法检测到。为什么宇宙中的物质都是物质，而不是反物质？这个问题的答案一定存在于粒子和反粒子之间的细微差别中，这种效应称为CP破坏。到目前为止观察到的CP破坏效应还不足以创造我们所看到的宇宙。更多CP破坏的最可能来源是中微子的相互作用。一个关键的观察是中微子有质量，不同类型的中微子可以在飞行中互换身份。T2 K实验已经对此进行了测量，并发现了CP破坏的诱人迹象。我们计划在这项工作的基础上，无论是在运行实验（T2 K和SBND），并在设计下一代中微子实验，将有更大的灵敏度。我们已经开发了一些工具来帮助中微子社区比较结果，并提高我们对中微子如何相互作用的理解。我们对Boulby Mine的访问为测试材料和探测器原型提供了宝贵的低背景实验室。最后但并非最不重要的是，我们寻求将HEP技术应用于工业和解决全球问题。我们正在使用为ATLAS开发的技术，以促进机器人技术的发展，并处理切尔诺贝利等高放射性环境。我们正在设计μ介子探测器，以搜索核违禁品和监测火山。我们的信号处理技术正被应用于改善心脏病患者的医学成像。我们在水切伦科夫中微子探测方面的专门知识正被用于一项旨在监测核不扩散条约遵守情况的实验。所有这些工作都建立在我们的STFC核心计划之上，以造福更广泛的世界。

项目成果

Search for excited electrons singly produced in proton-proton collisions at $$\sqrt{s} ~=~13~\text {Te}\text {V}$$ with the ATLAS experiment at the LHC

利用大型强子对撞机的 ATLAS 实验，在 $$sqrt{s} ~=~13~ ext {Te} ext {V}$$ 处搜索质子-质子碰撞中单独产生的激发电子

• DOI: 10.1140/epjc/s10052-019-7295-1
• 发表时间: 2019
• 期刊: The European Physical Journal C
• 作者: Aaboud M

Measurements of inclusive and differential fiducial cross-sections of $$t\bar{t}\gamma $$ production in leptonic final states at $$\sqrt{s}=13~\text {TeV}$$ in ATLAS

ATLAS 中 $$sqrt{s}=13~ ext {TeV}$$ 轻子最终状态下 $$tar{t}gamma $$ 产生的包含和微分基准横截面的测量

• DOI: 10.1140/epjc/s10052-019-6849-6
• 发表时间: 2019
• 期刊: The European Physical Journal C
• 作者: Aaboud M

Combination of Searches for Invisible Higgs Boson Decays with the ATLAS Experiment

• DOI: 10.1103/physrevlett.122.231801
• 发表时间: 2019-06-13
• 期刊: PHYSICAL REVIEW LETTERS
• 影响因子: 8.6
• 作者: Aaboud, M.;Aad, G.;Zhang, Z.
• 通讯作者: Zhang, Z.

Search for Higgs boson decays into a pair of light bosons in the bbμμ final state in pp collision at s=13TeV with the ATLAS detector

使用 ATLAS 探测器在 s=13TeV 的 pp 碰撞中寻找希格斯玻色子衰变为 bbμμ 最终态的一对轻玻色子

• DOI: 10.1016/j.physletb.2018.10.073
• 发表时间: 2019
• 期刊: Physics Letters B
• 影响因子: 4.4
• 作者: Aaboud, M.;Aad, G.;Abbott, B.;Abdinov, O.;Abeloos, B.;Abhayasinghe, D.K.;Abidi, S.H.;AbouZeid, O.S.;Abraham, N.L.;Abramowicz, H.
• 通讯作者: Abramowicz, H.

Search for four-top-quark production in the single-lepton and opposite-sign dilepton final states in p p collisions at s = 13 TeV with the ATLAS detector

使用 ATLAS 探测器在 s = 13 TeV 的 p p 碰撞中搜索单轻子和相反符号双轻子最终状态中的四顶夸克产生

• DOI: 10.1103/physrevd.99.052009
• 发表时间: 2019
• 期刊: Physical Review D
• 影响因子: 5
• 作者: Aaboud M