Institute for Particle Physics Phenomenology, Oct 2018 - Sept 2020

粒子物理学的研究告诉我们关于物质在非常小的尺度上的本质。当我们把长度尺度降低到原子的长度尺度10 ^（-10）米以下，并超过原子核的长度尺度10 ^（-15）米时，我们就进入了粒子物理学的领域。在这个领域中，有三种被很好地识别的相互作用。第一种是强相互作用，它负责夸克和胶子的结合，产生质子、中子和其他统称为强子的粒子。第二，电弱相互作用，负责从物质中辐射光子（光）和弱力载体的辐射，1983年在CERN发现的W和Z玻色子。第三，希格斯玻色子的相互作用。希格斯玻色子于2012年在欧洲核子研究中心被发现。所有这些成分的相互作用都受到数学结构的控制，称为电磁，弱和强相互作用的标准模型（SM）规范理论。这一理论经受住了各种加速器带来的所有挑战，其中最新和最具活力的是LHC。证实了电磁与弱相互作用的统一，证明并检验了零分之一的零分之一。强相互作用效应已被测试到百分比水平。夸克，强子的成分，有六种不同的类型，它们被称为味。味道现象在塑造SM的整体结构方面与规范原理有着同样的贡献，正是味道的存在赋予了SM家族和生成结构。在夸克部分，SM对色弱现象的描述和CKM对混合和CP破坏的描述在百分之几的水平上得到了验证。在轻子区，轻子的味道是电子、μ子、τ子和它们的相关中微子。中微子振荡的观测以及中微子具有质量的结论要求扩展SM。对带电轻子和中性轻子的详细检查越来越重要。2015年，大型强子对撞机（LHC）开始加速并碰撞质子，其能量比以往任何时候都高得多，13 TeV。大型强子对撞机的高能量范围将允许希格斯玻色子的详细研究和TeV尺度物理的探索。然而，LHC实验比以前的任何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需要实验学家和理论家之间的密切合作。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。新物理学的可能线索需要与SM之外的不同物理模型进行比较，以解开TeV尺度物理学的潜在结构。IPPP已经与英国和国际实验团体建立了密切的联系，并处于最佳位置，可以帮助英国最大限度地为理解LHC数据做出贡献。一旦新物理学的能量尺度被确定，将在规划和设计下一代粒子物理实验方面做出巨大努力。IPPP将继续在评估物理潜力和设计未来加速器方面发挥作用。未来十年将是我们理解微观世界的关键。IPPP将解决有关电弱对称性破缺、时空结构、味物理学和CP破坏、中微子和轻子味破坏以及粒子物理学如何与天体物理学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.