Particle Theory at the Higgs Centre

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(SM)。目前，我们对自然最根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更高的能量碰撞质子，并观测到了足够多的碰撞，发现了显著的过剩，这与SM的希格斯玻色子一致。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，大型强子对撞机正在获取更高能量的数据，很快就会变得更加清楚，是不是在TeV尺度上有更多的物理现象，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，欧洲普朗克卫星给出了宇宙微波背景(CMB)最精确的测量结果，确定最能描述宇宙大尺度性质背后的物理基础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，无论是在小范围还是大范围内，这都是基础物理学的变革性时代。我们在爱丁堡希格斯理论物理中心的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)描述了造成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距离尺度上发生变化。该小组还致力于使用这些理论来改进现有场论中的计算。最近发现的QCD振幅和GR之间的关系，也就是所谓的“双重复制”，为我们提供了对引力现象的新见解。总而言之，我们的研究将涉及与探索LHC数据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、粒子物理学和物理本身的本质。

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.