2012 Consolidated Grant Supplement

爱丁堡大学粒子物理研究小组参加了日内瓦大型强子对撞机的研究方案。大型强子对撞机是迄今为止建造的最复杂的机器，它创造的能量密度和温度条件存在于大爆炸后大约10^-12秒，当时粒子存在于非常不同的条件下。在这些条件下，新粒子就可以被创造出来供我们研究。在爱丁堡，我们在两个不同的领域工作。在第一个实验中我们进行LHCb实验。在20世纪60年代之前，人们一直认为物理定律在粒子与反粒子交换和粒子宇称颠倒的联合操作下是对称的。在这种条件下，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。在粒子物理的标准模型（SM）中，这体现在通过CKM矩阵产生的CP违背现象中。CP违背对于理解早期宇宙至关重要。在早期，物质和反物质的数量是相等的。在CPT对称和热平衡的一般假设下，这种情况将在宇宙膨胀时保持不变。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，那么物质对反物质的不平衡就有可能产生。这种不平衡仅为10^9的1分之一，但足以解释宇宙的存在。这些条件要求CP违反了物理定律。鉴于粒子物理学和宇宙学之间有着深远的联系，实验人员多年来一直在寻求理解这一现象。b夸克区是我们进一步了解的最好地方，这是LHCb实验的领域。LHCb是进一步这些研究的下一代实验，并将以数量级提高许多测量的准确性。在第二个领域，我们致力于ATLAS实验。ATLAS是两个能够研究质子碰撞产生的各种粒子的探测器之一，可以解决基本问题。最广为人知的问题是质量的起源，而人们正在寻找的最著名的粒子是希格斯玻色子。希格斯粒子是必要的，因为美丽的对称性（规范对称）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，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将证明这是正确的。ATLAS研究的另一个领域是寻找超对称，即我们所知道的所有粒子都有一个所谓的超级伙伴，其自旋相差半单位。如果这被证明是真的，它将有助于解决许多问题。它最重要的结果之一将是暗物质的候选者，暗物质约占我们宇宙的25%，而我们对它一无所知。我们也在努力规划、设计和开发2018年左右升级的LHC探测器。豆子的强度将增加，探测器记录的数据速率将增加几个数量级。这就需要开发新的探测器和电子设备。在这项拨款申请中，我们要求支持爱丁堡粒子物理研究小组，包括学术人员和博士后研究人员，以进一步发展所有这些领域。

The Particle Physics Research Group at the University of Edinburgh participates in the programme of research at the Large Hadron Collider in Geneva. The LHC is the most complex machine ever built, and creates conditions of energy density and temperature which existed at approximately 10^-12 seconds after the big bang when particles existed under very different conditions. With these conditions new particles can be created which we can study. At Edinburgh we are working in two different areas.In the first of these we work at the LHCb experiment. Prior to the 1960s, it had been thought that the laws of physics were symmetric under the combined operations of exchanging particle for anti-particle and reversing the parity of the particle. Under such conditions 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. In terms of the Standard Model (SM) of particle physics this is embodied in the phenomenon of CP violation arising through the CKM matrix. CP violation is essential to understanding the early universe. At early times there were equal amounts of matter and anti-matter. Under general assumptions of CPT symmetry and thermal equilibrium, this situation would have remained so as the universe expanded. During this 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 were met, then it would be possible for a small imbalance of matter over anti-matter to accrue. This imbalance would be only 1 part in 10^9, but would be sufficient to explain the existence of the universe. These conditions demand that CP is violated in the laws of physics. Given this far-reaching link between particle physics and cosmology, experimenters have been seeking to understand this phenomenon for many years. The b-quark sector is the best place to further our understanding and this is domain of the LHCb experiment. LHCb is the next generation experiment to further these studies and will improve the accuracy of many measurements by orders of magnitude.In the second area we work at the ATLAS experiment. ATLAS is one of two detectors able to study a wide variety of particles created from the collision of protons, and can address fundamental questions. The most well know question is that of the origin of mass, and the most famous particle being sought is the Higgs boson. The Higgs is necessary because the beautiful symmetry (gauge 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. Discovery of the Higgs boson would be the proof that that this is true. Another area addressed by ATLAS is that of the search for supersymmetry whereby all particles we know of have a so called super-partner differing by one half unit of spin. If this proved to be true it would help solve many problems. One of its most important consequences would be a candidate for dark matter, which makes up about 25% of our Universe, and about which we know nothing.We are also working hard on the planning, design and development for the upgraded detectors at the LHC for around 2018. The intensity of the beans will be increased and the data rates recorded by the detectors will increase by orders of magnitude. This requires development of new detectors and electronics. In this grant application we request support for the Edinburgh Particle Physics Research Group, including academic staff and post-doctoral researchers to further all of these areas.