Particle Theory at the Higgs Centre

自然界中有两种基本力：一种是在亚原子尺度上负责粒子相互作用的力，另一种是负责宇宙大尺度结构的力。前者由量子场论（QFT）描述，如标准模型（SM）。目前，我们对自然最基本的理解正处于十字路口。2012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高的能量碰撞质子，并观察到足够的碰撞，以找到一个显着的过剩，与希格斯玻色子的SM一致。近年来，很明显，这确实是一个SM希格斯粒子，负责产生矢量玻色子，轻子和夸克的质量。目前，LHC正在获取更高能量的数据，并且应该很快就会变得更清楚，是否有更多的TeV级物理，或者我们是否需要建造能够达到更高能量的机器。在大尺度上，欧洲普朗克卫星对宇宙微波背景辐射（CMB）进行了最精确的测量，确定最能描述宇宙大尺度特性的粒子物理模型是一个悬而未决的问题。2016年，LIGO宣布探测到引力波，标志着天体物理学新篇章的开始。因此，无论是在小尺度还是大尺度上，这都是基础物理学的变革时期。我们在爱丁堡希格斯理论物理中心的研究计划旨在成为这些新发现的前沿：事实上，彼得·希格斯本人就是这里的名誉教授。具体来说，我们提供理论计算，使用笔和纸，以及最强大的超级计算机，由于已知的物理学，在LHC中可以看到大量的背景过程，以及在各种新物理模型中预期的微小信号，以便区分信号和背景，从而最大限度地提高LHC的发现潜力。与此同时，我们将试图理解所有可能开始出现的自然力量的更完整的图景。爱因斯坦的广义相对论（GR）描述了大尺度结构的基本力。在过去的三十年里，弦理论已经成为一个概念丰富的理论框架，调和了GR和QFT。弦论的低能极限是超引力（SUGRA），这是GR的非平凡扩展，其中宇宙由具有额外几何数据的时空描述。该小组的成员开创了方法来推导弦理论的可观测宇宙学后果，研究GR所预测的几何概念如何在非常小的（“弦”）距离尺度上变化。该小组还致力于使用这些理论来改进现有场论的计算。最近发现的QCD振幅和GR之间的关系，被称为“双副本”，提供了新的洞察力引力现象。总之，我们的研究将冲击在理论和计算方面相关的探测LHC数据的现象，也将涵盖广泛的主题QFT和引力方面的弦理论，冲击宇宙学，粒子物理学和物理学本身的本质。

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(SM). Currently, our understanding of Nature at the most fundamental level is at the crossroads. In 2012, the LHC at CERN collided protons at higher energies than ever before, and observed sufficient collisions to find a significant excess, consistent with the Higgs boson of the SM. Over recent years it has become evident that this is indeed a SM Higgs, responsible for generating masses for vector bosons, leptons and quarks. Currently data at even higher energies is being taken at LHC, and it should soon become clearer whether there is more physics at the TeV scale, or whether we need to build machines capable of going to even higher energies. At large scales the European Planck satellite has given the most precise measurements of the cosmic microwave background (CMB) and it is an open question to determine the particle physics model best capable of describing the physics underlying the large scale properties of the Universe. In 2016 the detection of gravitational waves was announced by LIGO, marking the start of a new chapter in astrophysics. Thus at both small and large scales, this is a transformative time in fundamental physics.Our programme of research at the Higgs Centre for Theoretical Physics in Edinburgh 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 by 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. The group is also engaged in using these theories to improve calculations in existing field theories. Recent discoveries of relationships between QCD amplitudes and GR, known as the 'double copy', offer new insight into gravitational phenomena.In summary, our research will impinge on both theoretical and computational aspects relevant to probing the phenomenology of 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 physics itself.