Institute for Particle Physics Phenomenology, Oct 2018 - Sept 2020

粒子物理研究让我们在很小的尺度上了解了物质的本质。当我们沿着低于原子长度的10^(-10)米的长度尺度向下移动，并超过原子核的长度尺度(10^(-15)米)，我们就进入了粒子物理学的领域。在这个领域中有三个公认的相互作用。第一，强相互作用，负责结合夸克和胶子产生质子、中子和其他粒子，统称为强子。第二，1983年在欧洲核子研究中心发现了电弱相互作用，它既负责从物质中辐射光子(光)，也负责弱作用力的载流子W和Z玻色子的辐射。第三，希格斯玻色子的相互作用。2012年，欧洲核子研究中心发现了希格斯玻色子。所有这些成分的相互作用都受一种数学结构的控制，这种结构被称为标准模型(SM)规范理论，即电磁、弱和强相互作用。到目前为止，这一理论经受住了各种加速器带来的所有挑战，其中最新和最有活力的是大型强子对撞机。证实了SM-电磁和弱相互作用的统一，并被证明和测试到每毫升一份。强烈的相互作用效应已被测试到百分之一的水平。夸克是强子的成分，有六种不同的类型，它们被称为香料。味觉现象和量规原理一样，在塑造SSM的整体结构方面做出了同样多的贡献，正是香味的存在赋予了SM它的家族和世代结构。在夸克区，对气味现象的SM描述以及混合和CP破坏的CKM图像现在在几个百分点的水平上得到了验证。在轻子领域，轻子的特征是电子、介子、介子和与它们相关的中微子。对中微子振荡的观察，以及中微子具有质量的结果，要求扩展SM。对带电轻子和中性轻子的详细研究越来越重要。2015年，大型强子对撞机(LHC)开始以比以往更高的能量(13TeV)加速和碰撞质子。大型强子对撞机的高能范围将允许详细研究希格斯玻色子和探索TeV尺度的物理。然而，LHC实验比任何以前的粒子物理实验都要复杂得多。在TeV尺度上确定物理学的本质将需要实验者和理论家之间激烈的合作努力。在理论方面，需要对SM过程进行高精度的计算，以区分新物理的可能信号和SM背景。新物理的可能线索需要与SM之外的不同物理模型进行比较，以便解开TeV尺度物理的基本结构。IPPP已经与英国和国际实验小组建立了密切的联系，并处于完美的地位，有助于最大限度地发挥英国对理解大型强子对撞机数据的贡献。一旦确定了新物理的能量尺度，将在规划和设计下一代粒子物理实验方面做出强有力的努力。IPPP将继续在评估物理潜力和未来加速器的设计方面发挥作用。下一个十年有望成为我们理解显微世界的关键。IPPP将解决有关电弱对称破缺、时空结构、味物理和CP破坏、中微子和轻子味破坏以及粒子物理如何与天体物理和宇宙学联系的基本问题。

Particle physics research informs us about the nature of matter onvery small scales. As we step down the length scales below the lengthscale of the atom, 10^(-10) meters, and past the length scale of theatomic nucleus, 10^(-15) meters, we enter the realm of particlephysics. In this realm there are three well identified interactions.First, the strong interactions, which are responsible for the bindingof quarks and gluons to produce protons, neutrons and other particlescollectively called hadrons. Second, the electroweak interactions,responsible both for the radiation of photons (light) from matter andthe radiation of the carriers of the weak force, the W and Z bosons,discovered at CERN in the 1983. Third, the interactions of the Higgsbosons. The Higgs boson was discovered at CERN in 2012.The interactions of all of these ingredients are controlled by amathematical structure, known as the Standard Model (SM) gauge theoryof electromagnetic, weak and strong interactions. This theory has sofar withstood all the challenges posed by various accelerators, ofwhich the latest and most energetic is the LHC. The SM is confirmed--- with the unification of electromagnetism and weak interactionsproved and tested to one part per mille. Strong interaction effectshave been tested to the per cent level. The quarks, the ingredients of the hadrons, come in six different typeswhich are referred to as flavours. Flavour phenomena have contributedas much as the gauge principle in shaping the overall structure of theSM and it is the existence of flavours that gives the SM its familyand generation structure. In the quark sector the SM description offlavour phenomena and the CKM picture of mixing and CP violation isnow verified at the few per cent level. In the lepton sector, theflavours of leptons are the electron, the muon and the tau and theirassociated neutrinos. The observation of neutrino oscillations, andthe consequence that neutrinos have mass, calls for an extension ofthe SM. Detailed examination of the charged and neutral leptons is of increasing importance.In 2015, the Large Hadron Collider (LHC) started to accelerate andcollide protons at much higher energies than ever before, 13 TeV. Thehigh energy reach of the LHC will allow the detailed study of theHiggs boson and exploration of TeV scale physics. However, the LHCexperiments are significantly more complex than any previous particlephysics experiment. Identifying the nature of physics at the TeV scalewill require intense collaborative efforts between experimentalistsand theorists. On the theoretical side, high-precision calculations ofSM processes are needed to distinguish possible signals of new physicsfrom SM backgrounds. Possible hints of new physics need to be comparedwith different models of physics beyond the SM in order to disentanglethe underlying structure of TeV-scale physics. The IPPP has alreadyestablished close connections with the UK and internationalexperimental groups and is perfectly placed to help maximise the UKcontribution to understanding the LHC data.Once the energy scale of new physics is identified, there will be astrong effort in planning and designing the next generation ofparticle physics experiments. The IPPP will continue its role inassessing the physics potential and the design of future accelerators.The next decade promises to be pivotal in our understanding of themicroscopic world. The IPPP will address fundamental questions aboutelectroweak symmetry breaking, the structure of space-time, flavourphysics and CP violation, neutrinos and lepton-flavour violation, andhow particle physics connects with astrophysics and cosmology.