Phenomenology from Lattice QCD and Collider Physics

格拉斯哥理论小组在亚原子世界的研究方面享有很高的声誉，并推动了我们对其运作方式的理解。这是为了揭示物质的基本成分和它们之间相互作用的本质。有两种方法，我们将使用这两种方法。一个是在标准模型的理论框架内进行非常精确的计算，我们相信标准模型正确地描述了我们迄今为止所看到的粒子以及自然界的强、弱和电磁力。这些精确的计算结果与实验结果之间的差异将为更全面地描述基本粒子物理学的更深层次的理论指明道路。第二种方法关注的是，如果所提出的更深层次的理论之一是正确的，我们可能会在现在出现的大型强子对撞机结果中看到什么。我们必须确保我们优化这些实验的分析，以尽可能多地学习。在过去，标准模型中的精确计算在如何处理强作用力的难题上失败了。这种力在组成原子核、质子和中子的粒子以及在高能碰撞中产生的大量被称为强子的类似粒子中很重要。这些粒子的成分是夸克，它们被强力的作用困在强子里。夸克的这种“约束”使得强子物理中强作用力的计算非常具有挑战性。然而，这个问题可以用点阵QCD的数值技术来解决。这种方法已经被格拉斯哥小组在强子质量的精确计算和与实验的比较中进行了彻底的测试，目前它作为一种精密工具被接受，在很大程度上是基于他们的工作。格拉斯哥继续引领进展，在这里我们提出进一步，更困难的计算，将预测更多的细节强子如何通过弱力从一种类型衰变到另一种类型。将精确的结果与实验结果进行比较，将使我们能够约束导致物质和反物质之间对称性破坏的弱力的参数。我们计划将这些计算中的现有误差减半，这将使我们能够非常严格地测试标准模型。格拉斯哥团队还将研究超越标准模型的理论，并对它们进行测试，这些理论可以用大型强子对撞机的数据来完成。例如，我们将提供在大型强子对撞机上可能看到的物理特征的现象学研究，以及它们如何区分不同的模型。这包括研究可能出现在某些模型中的新粒子，以确定它们的性质。特别是，我们将开发研究顶夸克物理学的方法，这将在大型强子对撞机上大量产生。顶部是我们所见过的最重的夸克，它为研究新物理学提供了一扇令人兴奋的窗口。这一领域的实验研究由格拉斯哥ATLAS小组领导，我们将与他们合作，提供详细测试顶夸克特性的方法，包括在标准模型场景之外可能出现的行为。我们还在开发新的方法来提高夸克和胶子如何影响散射实验的准确性，这对大型强子对撞机物理学很有用，但也可能导致除QCD之外的其他理论的见解。未来四年将是理论粒子物理学非常激动人心的时期，格拉斯哥的目标是走在这项工作的前沿。

The Glasgow theory group has a strong reputation in studies of the subatomic world, and pushing forward our understanding of how it works. This is aimed at uncovering the fundamental constituents of matter and the nature of the interactions that operate between them. There are two approaches to this, and we will use both of them. One is to perform very accurate calculations within the theoretical framework of the Standard Model that we believe correctly describes the particles that we have seen so far and the strong, weak and electromagnetic forces of Nature. Discrepancies between these accurate calculations and what is seen in experiments will then point the way to a deeper theory that describes fundamental particle physics more completely. The second method is concerned with what we might see in LHC results, now appearing, if one of the suggested deeper theories is correct. We must make sure that we optimise the analysis of these experiments to learn as much as possible. Accurate calculations in the Standard Model have foundered in the past on the difficult problem of how to handle the strong force. This force is important inside particles that make up the atomic nucleus, the proton and neutron and a host of similar particles called hadrons produced in high energy collisions. The constituents of these particles are quarks, and they are trapped inside hadrons by the behaviour of the strong force. This 'confinement' of quarks makes calculations of the effect of the strong force on the physics of hadrons very challenging. It can be tackled, however, using the numerical techniques of lattice QCD. This method has been tested thoroughly by the Glasgow group in precision calculations of hadron masses and their comparison to experiment, and its current acceptance as a precision tool is based in no small part on their work. Glasgow continues to lead progress and here we propose further, harder calculations that will predict more details of how hadrons decay from one type to another via the weak force. The comparison of accurate results with experiment will allow us to constrain the parameters of the weak force that give rise to violations of symmetry between matter and antimatter. We plan to halve existing errors for these calculations and that will allow us to test the Standard Model very stringently. The Glasgow team will also investigate theories that go beyond the Standard Model and tests of them that can be done with LHC data. For example, we will provide phenomenological studies of possible physics signatures that could be seen at LHC and how they would distinguish between models. This includes studying new particles that would be present in some models with a view to establishing their properties. In particular we will develop methods for studying the physics of top quarks, which will be produced copiously at LHC. The top is the heaviest quark that we have seen, and it provides an exciting window into new physics. Experimental studies in this area are being led by the Glasgow ATLAS group and we will coordinate with them to provide ways of testing top quark properties in detail, including behaviour that could arise in beyond the Standard Model scenarios. We are also developing new methods for increasing the accuracy of how quarks and gluons affect scattering experiments, which is useful for LHC physics, but may in addition lead to insights in other theories besides QCD. The next four years will be a very exciting time for theoretical particle physics and Glasgow aims to be at the forefront of this work.