Particle Theory at the Tait Institute

自然界中有两种基本力：负责亚原子尺度上的粒子相互作用的力和负责宇宙大尺度结构的基本力。前者由量子场论(QFT)描述，如标准模型。目前，我们对自然最根本的理解正处于十字路口。去年，欧洲核子研究中心的大型强子对撞机以比以往任何时候都更高的能量对撞质子，今年应该会有足够的对撞开始探索TeV尺度的物理。目前还没有人知道这些数据会揭示什么。然而，有非常充分的理由相信，最终会发现一些根本性的新东西，这可能会改变我们对基础物理学的理解，使未来几年成为一代人或更长时间以来最令人兴奋的时期。这些发现可能是新类型的粒子，如希格斯玻色子，新类型的对称性，如超对称性，甚至是更戏剧性的东西，如额外维度或迷你黑洞。我们滚动的粒子物理理论研究计划旨在走在这些新发现的前沿：事实上，彼得·希格斯本人就是这里的荣誉退休教授。具体地说，我们使用纸笔和最强大的超级计算机，对大型强子对撞机上因已知物理而看到的大量背景过程以及各种新物理模型中预期的微小信号进行理论计算，以区分信号和背景，从而最大限度地发挥大型强子对撞机的发现潜力。同时，我们将尝试了解可能开始出现的所有自然力量的更完整的图景。爱因斯坦的广义相对论(GR)描述了导致大尺度结构的基本力。在过去的三十年里，弦理论作为一个概念丰富的理论框架出现在GR和QFT之间。弦理论的低能量极限是超引力(Sugra)，这是GR的一个非平凡的扩展，其中宇宙由一个带有额外几何数据的时空来描述。该小组的成员开创了推导弦理论可观察到的宇宙学结果的方法，研究了GR所依据的几何概念如何在非常小的(弦的)距离尺度上变化，以及Sugra背景的系统分类。该小组还致力于使用这些理论来改进现有场论中的计算。总而言之，我们的研究将涉及与探索大型强子对撞机数据的现象学相关的理论和计算方面，还将涵盖QFT和弦理论的引力方面的广泛主题，影响宇宙学、粒子物理学和弦理论本身的本质。

There are two types of fundamental forces in Nature: Those responsible for particle interactions at subatomic scales and those responsible for the large scale structure of the universe. The former is described by Quantum Field Theories (QFT) such as the Standard Model. Currently, our understanding of Nature at the most fundamental level is at the crossroads. Last year, the LHC at CERN collided protons at higher energies than ever before, and this year there should be sufficient collisions to begin to explore physics at the TeV scale. Nobody yet knows what these data will reveal. However, there are very good reasons to believe that something fundamentally new will eventually be discovered, which might transform our understanding of basic physics, making the next few years the most exciting time for a generation or more. The discoveries could be new types of particle, such as the Higgs boson, new kinds of symmetries such as supersymmetry, or indeed something even more dramatic such as extra dimensions or mini black holes. Our rolling programme of research in Particle Physics Theory is designed to be at the forefront of these new discoveries: indeed Peter Higgs himself is Emeritus Professor here. Specifically, we provide theoretical calculations, using pen and paper, and the most powerful supercomputers, of both the huge number of background processes to be seen at LHC due to known physics, and the tiny signals expected in various models of new physics, in order to discriminate between signal and background, and thus maximise the discovery potential of the LHC. In parallel, we will attempt to understand the more complete picture of all the forces of Nature that may begin to emerge. The fundamental force responsible for large scale structure is described Einstein's General Theory of Relativity (GR). During the last three decades, string theory has emerged as a conceptually rich theoretical framework reconciling both GR and QFT. The low-energy limit of String Theory is supergravity (SUGRA), a nontrivial extension of GR in which the universe is described by a spacetime with additional geometric data. Members of the group have pioneered approaches to deriving observable cosmological consequences of String Theory, to studying how the geometrical notions on which GR is predicated change at very small ('stringy') distance scales, and the systematic classification of SUGRA backgrounds. The group is also engaged in using these theories to improve calculations in existing field theories. In summary, our research will impinge on both theoretical and computational aspects relevant to probing the phenomenology of incoming LHC data, and will also encompass a wide range of topics in QFT and gravitational aspects of String Theory, impinging on cosmology, particle physics and on the very nature of String Theory itself.