Experimental Particle Physics at the University of Edinburgh

爱丁堡实验粒子物理小组目前正在进行三个不同的实验，我们也在进行几个未来的项目。大型强子对撞机（LHC）上的ATLAS实验：ATLAS是两个能够研究由最高能量的质子碰撞产生的各种粒子的探测器之一，它解决了一些基本问题。最著名的是质量的起源。美丽的对称性是我们理解粒子相互作用的基础，它本质上要求所有粒子都是无质量的。这是不可能的，而这个优雅的解决方案现在被称为希格斯机制。希格斯玻色子的发现证实了这一点，现在我们必须非常详细地测量它的性质。ATLAS研究的另一个领域是寻找新的重粒子，如新的重希格斯粒子或超对称粒子，这些粒子是在试图解决标准模型缺陷的模型中预测的，比如为什么它们是暗物质。在大型强子对撞机上进行的LHCb实验。在20世纪60年代之前，人们一直认为物质和反物质会以同样的方式运动。然而，人们发现这种对称性被打破了，物质和反物质的行为方式并不相同。这体现在CP违背现象中，对理解早期宇宙至关重要。大爆炸后不久，物质和反物质的数量相等。在膨胀和冷却过程中，物质和反物质会湮灭成光子，留下一个充满辐射的宇宙，但没有恒星和星系。Sakarov在1967年指出，如果满足三个条件，包括CP违反，那么就有可能产生物质对反物质的微小不平衡，这就足以解释宇宙的存在。LHCb测量具有至少一个b或反b夸克的粒子和反粒子的行为差异（CP违逆），并寻找这些粒子的非常罕见的衰变，这些衰变可能受到未观察到的重粒子的影响。LUX实验，是目前世界领先的寻找暗物质的仪器。众所周知，大约27%的宇宙是由暗物质组成的——暗物质是某种形式的物质，它不会以一种产生辐射的方式相互作用，也不会产生其他容易观察到的特征。有许多理论候选者，解决这个谜团必须包括直接探测我们银河系的暗物质。早期宇宙中弱相互作用大质量粒子的热产生自然导致了今天正确的暗物质丰度，并且前面提到的大多数超对称模型都包含这样的粒子。许多其他动机良好的理论也提出了可能被寻找的粒子。我们也在努力设计、开发和建造升级后的LHC探测器，预计在2020年左右完成。光束的强度将增加，探测器记录的数据速率将增加几个数量级。这需要建造新的探测器来精确测量长寿命粒子的轨迹，测量切伦科夫光子来确定它们的速度，更快更强大的模拟，以及处理大量数据速率的新方法。我们还在建设和运行LUX-ZEPLIN项目，预计将在未来十年主导对暗物质的直接搜索。我们的工作是模拟，10吨液态氙的控制系统，以及分析。我们最近通过加入DUNE和Hyper-K实验来开始活动中微子物理。自然界最有趣的事实之一是，中微子只有三种，直到最近才被认为是无质量的。精确测量两种粒子之间的“混合”以及在中微子中寻找CP违逆是很重要的。

The Edinburgh Experimental Particle Physics group is currently working in three different running experiments and we are also working on several future projects.The ATLAS experiment at the Large Hadron Collider (LHC): ATLAS is one of two detectors able to study a wide variety of particles created from the collision of protons at the highest energies ever created, and it addresses fundamental questions. The most well known is that of the origin of mass. The beautiful symmetry which underlies our understanding of particle interactions inherently demands that all particles are massless. This cannot be the case, and the elegant solution put forward is now known as the Higgs mechanism. The discovery of the Higgs boson has verified this, and now we must measure its properties in great detail. Another area addressed by ATLAS is the search for new heavy particles such as new heavy Higgs like particles or supersymmetric particles, which are predicted in models trying to address shortcomings of the Standard Model, such as why their is dark matter.The LHCb experiment at the LHC. Prior to the 1960s, it had been thought that matter and anti-matter would behave in the same way. However, it was discovered that this symmetry was violated, and that matter does not behave in an identical way to anti-matter. This is embodied in the phenomenon of CP violation and is essential to the understanding of the early universe. Shortly after the big bang there were equal amounts of matter and anti-matter. During expansion and cooling, matter and anti-matter would have annihilated into photons to leave a universe full of radiation, but no stars and galaxies. It was shown in 1967 by Sakarov that if three conditions, including CP violation, were met, then it would be possible for a small imbalance of matter over anti-matter to accrue, which would be sufficient to explain the existence of the universe. LHCb measures differences (CP violation) in behaviour of particles and antiparticle with at least one b or anti-b quark and searches for very rare decays of these particles, which could be affected by heavy unobserved particles. The LUX experiment, which is the current world-leading apparatus searching for dark matter. It is well known that some 27% of the Universe is comprised of Dark Matter - that is matter of some form which does not interact in a way which produces radiation, or other easy to observe signatures. There are many theoretical candidates and resolution of this mystery must include the direct detection of our own galactic dark matter. Thermal production of Weakly Interacting Massive Particles in the early universe naturally results in the correct dark matter abundance today, and most supersymmetry models mentioned earlier contain such particles. Many other well-motivated theories also invoke particles that may be searched for. We are also working hard on the design, development and construction of the upgraded detectors at the LHC for around 2020. The intensity of the beams will be increased and the data rates recorded by the detectors will increase by orders of magnitude. This requires building new detectors for precisely measuring trajectories of longlived particles, for measuring Cherenkov photons to determine their speed, and faster and more powerful simulation, and new ways to handle the massive data rates. We are also constructing and operating the LUX-ZEPLIN project, expected to dominate direct searches for dark matter in the next decade. We work on simulations, control systems for the 10 tonnes of liquid xenon, and analysis.We have recently started an activity neutrino physics by joining both the DUNE and Hyper-K experiments to be constructed. One of the most interesting fact of nature is that there are only three species of neutrinos, which until recently were thought to be massless. It is important to measure precisely the "mixing" between the species and to search for CP violation in neutrinos.