Birmingham Experimental Particle Physics Consolidated Grant

总的来说，粒子物理学，特别是通过希格斯玻色子来理解质量起源的探索，是当前公众意识的主流。随着欧洲核子研究中心(CERN)的大型强子对撞机(LHC)变得越来越强大，该领域从未有过比这更令人兴奋的时刻。伯明翰参与了四个主要的大型强子对撞机实验中的三个，以及使用固定目标的较小规模的CERN实验，这在英国大学中是独一无二的。我们研究在这些实验中观察到的粒子碰撞和衰变，目的是确定物质的最终结构和自然力。我们最大的活动是与ATLAS的合作，小组成员戴夫·查尔顿是该合作的副发言人。阿特拉斯的设计目的是以实验室有史以来达到的最高能量研究粒子物理学的广泛方面，首要任务是寻找希格斯玻色子。在每秒发生的多达10亿次碰撞中，只有大约400次可以被永久记录和分析。我们的ATLAS团队建立、维护和运行了ATLAS“触发器”的主要部分，也就是实验的电子大脑，它的任务是选择有趣的事件，如候选希格斯玻色子，并在碰撞发生后的百万分之二秒内将数据速率降低1000倍。我们还非常积极地分析结果数据，一个特别强大的团队致力于希格斯搜索，另一个团队调查顶级夸克的产生和衰变。作为已知粒子中最重的，顶夸克对以前未知的物理具有极好的敏感性。虽然大型强子对撞机时代之前顶层夸克样本很小，但ATLAS已经收集了近10万个事件。大型强子对撞机预计将运行到2030年左右，但在其生命周期中将需要几次关闭时间，届时加速器和探测器将得到改进。我们已经在努力升级我们的触发器，以提高其选择能力，并使其能够应对预计从2018年开始增加的撞击率。展望未来，我们将利用我们在将电子设备直接连接到硅基探测器方面的专业知识，为更换探测器的内部做出重大贡献，这将在2022年左右使用。在ATLAS之后，我们的第二个关键活动领域是了解重夸克的复杂衰变。在LHCb实验中，我们正在通过寻找b夸克和它们的反夸克的衰变特征之间的微小差异来研究宇宙物质-反物质不对称的起源。我们是LHCb的新手，于2011年3月加入，并在模拟探测器和使用全球计算网格执行分布式分析方面承担了基本的技术责任。在接下来的几年里，我们的目标是进一步发展这些角色以及我们的物理分析，目前我们的分析重点是b型风味粒子的罕见衰变。我们的NA62小组研究奇异粒子的衰变，以寻找新的物理，如超对称性。下一个授权期对NA62来说将是至关重要的，因为它需要数据来研究一个极其罕见的过程，在这个过程中，一种奇怪的粒子--介子--衰变产生一个由轻夸克和两个中微子组成的介子。这一过程在每100亿kAon衰变中只发生一次，预计在两年内只会发生80次。任何更大速率的迹象都将是新物理学的一个非常明确的迹象。该小组正在领导NA62探测器建设和数据分析的几个方面。最后，该小组包括未来可能的“LHeC”项目的主要支持者，该项目旨在使电子与大型强子对撞机质子碰撞，以及长期存在的线性电子-正电子对撞机项目。我们将继续担任这些领导角色，并准备在机会出现时加强我们的参与。

Particle physics in general, and particularly the quest to understand the origins of mass through the Higgs boson, are in the mainstream of current public consciousness. With the CERN Large Hadron Collider (LHC) going from strength to strength, there has never been a more exciting time in the field. Birmingham is unique among UK universities in being involved in three of the four main LHC experiments, as well as a smaller scale CERN experiment which uses a fixed target. We study the particle collisions and decays observed in these experiments with the aim of determining the ultimate structure of matter and the forces of nature.Our biggest activity is with the ATLAS collaboration, for which group member Dave Charlton is the deputy spokesperson. ATLAS is designed to study wide-ranging aspects of particle physics at the highest energies ever reached in the laboratory, the first priority being the search for the Higgs boson. From up to a billion collisions taking place per second, only around 400 can be permanently recorded and analysed. Our ATLAS group built, maintains and operates a major part of the ATLAS `trigger', the electronic brain of the experiment, which has the task of selecting interesting events such as candidate Higgs bosons, and reducing the data rate by a factor of 1000 within two millionths of a second after collisions take place. We are also very active in analysing the resulting data, with a particularly strong team working on Higgs searches and another investigating the production and decays of top quarks. Being the heaviest of the known particles, top quarks offer excellent sensitivity to previously unknown physics. Whilst top quark samples were small before the LHC era, ATLAS has already collected approaching 100,000 events.The LHC is expected to operate until around 2030, but will need several shut-down periods during its lifetime, when the accelerator and detectors will be improved. We are already working towards an upgrade of our trigger to improve its selection capabilities and enable it to cope with the increased collision rates expected from 2018. Looking even further to the future, we will use our expertise in the bonding of electronics directly onto silicon-based detectors to make major contributions to a replacement for the inner part of the detector, which will be needed in around 2022.Beyond ATLAS, our second key area of activity is in understanding the complex decays of heavy quarks. At the LHCb experiment, we are investigating the origins of the matter-antimatter asymmetry of the Universe by searching for tiny differences between the decay characteristics of b quarks and their antiquarks. We are relative newcomers to LHCb, having joined in March 2011 and taken on essential technical responsibilities in simulating the detector and enabling the use of the world-wide computing grid to perform distributed analysis. In the next few years, we aim to further develop these roles as well as our physics analyses, which are currently focused on rare decays of b flavoured particles. Our NA62 group studies the decays of strange particles to search for new physics such as supersymmetry. The next grant period will be crucial for NA62, as it takes data to study an ultra rare process in which a strange particle, the kaon, decays to produce a pion, which is made of light quarks, and two neutrinos. This process occurs only once in every 10 billion kaon decays and only 80 events are expected in a two year run. Any hint of a larger rate would be a very clear indication of new physics. The group is leading several aspects of NA62 detector construction and data analysis. Finally, the group contains central proponents of a possible future `LHeC' project to collide electrons with the LHC proton beam, as well as the long-standing linear electron-positron collider project. We will continue in these leadership roles and be ready to step up our involvement should the opportunity arise.