The Lancaster, Manchester, Sheffield Consortium for Fundamental Physics: Particle Physics from the LHC to the Universe

粒子物理学就是要理解自然界的基本组成部分以及它们之间的相互作用。多年来，物理学家已经发展出粒子物理学的标准模型，它在描述范围非常广的自然现象方面非常成功，从光如何工作、原子为什么形成到恒星内部的复杂运作以及大爆炸后最初几分钟内原子核的合成。然而，我们知道标准模型并不是故事的全部，因为它留下了许多未解之谜。我们的建议集中在这些悬而未决的问题上，以及科学家们希望在未来几年通过大型强子对撞机（LHC）等实验或使用普朗克卫星进行的观测来解决这些问题的方式。在大型强子对撞机上发现希格斯玻色子是我们探索质量起源的一个重要里程碑。然而，这当然不是事情的全部。大型强子对撞机的实验正在努力测量它的性质。他们也在寻找新的粒子，比如超对称和其他新的物理理论所预测的粒子。如果超对称被发现，那么它将为解释暗物质的起源提供希望，暗物质构成了宇宙中已知存在的大部分物质。我们联盟的科学家探索超对称理论和暗物质。我们使用来自大型强子对撞机等实验的数据来确定哪些可能的新理论是由数据所允许的，并提出在实验中探索它们的新方法。在大型强子对撞机上产生的任何“新物理”都是两个质子相互撞击的结果，这是一个非常复杂的环境，通常与其他粒子的“喷流”有关。我们联盟的成员将探索如何利用这些喷射来更多地了解相关的新物理：我们对新物理发生的环境了解得越好，我们就越能了解新物理本身。这是一项复杂的工作，经常需要计算机模拟粒子碰撞。我们的成员是这些模拟方面的专家，他们计划如何使模拟更加精确，如果我们想要充分利用LHC令人兴奋的数据，这是必要的。粒子物理学的标准模型在解释宇宙的早期历史时也是不够的，当时宇宙是热的和稠密的。现在非常有力的证据表明，历史始于一个加速扩张的时代，即通货膨胀。我们是研究通货膨胀及其后果的专家。暴胀使宇宙没有任何特征，除了微小的量子涨落导致宇宙中物质和能量的密度随位置而变化。这些最初很小的变化逐渐成为可观察到的影响。其中一个影响是形成了遍布夜空的数十亿个星系。另一种方法是在宇宙微波背景辐射（CMB）上留下微小的印记，这是一种微弱的微波辐射，宇宙沐浴在其中。普朗克卫星对宇宙微波背景进行了细致的研究。我们站在解释普朗克数据的最前沿，希望能够确定早期宇宙的各种理论中哪些被排除在外，哪些仍然可行。标准模型的缺陷还在进一步扩大，因为它不能解释普通物质的数量，甚至不能解释普通物质的存在。我们的科学家将利用这一点来限制标准模型之外的可能物理现象，并且要做到这一点，他们需要掌握宇宙在膨胀结束期间和之后的动力学。最后但并非最不重要的是，我们希望更好地理解神秘的“暗能量”，它驱动着当前和未来的宇宙加速：一种可能性是，这是因为爱因斯坦的引力理论并不完全正确，这是我们将探索的东西。

Particle physics is all about understanding the elementary building blocks of nature and their interactions. Over the years, physicists have developed the Standard Model of particle physics, which is extremely successful in describing a very wide range of natural phenomena from things as basic as how light works and why atoms form through to the complicated workings inside stars and the synthesis of nuclei in the first few minutes after the Big Bang. However, we know that the Standard Model is not the whole story for it leaves many questions unanswered. Our proposal focuses on these unanswered questions and the way that scientists hope to address them in the coming years using experiments like the Large Hadron Collider (LHC) or observations like those that will be made using the Planck satellite.The discovery at the LHC of a Higgs boson was a major milestone in our quest to understand the origin of mass. It is certainly not, however, the whole story. The LHC experiments are working hard to measure its properties. They are also searching for new particles such as those predicted by supersymmetry and other new physics theories. If supersymmetry is discovered then it offers the hope to explain the origin of the Dark Matter that makes up a large fraction of the material that is known to exist in the Universe. The scientists in our consortium explore the theory of supersymmetry and dark matter. We use data from experiments like the LHC to identify which of the many possible new theories are allowed by the data and to suggest new ways to explore them in experiments. Any "new physics" produced at the LHC will be produced as a result of smashing two protons into each other, a very complicated environment, usually in association with "jets" of other particles. Members of our consortium will explore how we can make use of these jets to learn more about the associated new physics: the better we understand the environment in which new physics occurs, the more we are able to learn about the new physics itself. This is a complicated business that often necessitates computer simulations of particle collisions. Our members are experts in these simulations and have plans on how to make them more accurate, which is necessary if we are to make the most of the exciting data from the LHC.The Standard Model of particle physics is also insufficient when it comes to explaining the early history of the Universe, when it was hot and dense. The evidence is now very strong that the history began with an era of accelerating expansion, called inflation. We are experts on inflation and its consequences. Inflation makes the Universe featureless, except for tiny quantum fluctuations that cause the density of matter and energy in the Universe to vary with position. These initially small variations grow to become observable effects. One effect is the formation of the billions of galaxies that populate the night sky. Another is to leave a tiny imprint on the cosmic microwave background radiation (CMB), a faint hum of microwave radiation in which the Universe is bathed. The CMB has been studied in exquisite detail by the Planck satellite. We are at the forefront of interpreting the Planck data in the hope of pinning down which of the various theories of the early universe are ruled out and which remain viable. The deficiencies of the Standard Model extend still further for it does not explain the amount nor even the existence of ordinary matter. Our scientists will use this to constrain possible physics beyond the Standard Model and to do that they need to master the dynamics of the Universe during and after the end of inflation. Last but not least, we hope to understand better the mysterious "Dark Energy" that drives the current and future acceleration of the Universe: one possibility is that it is because Einstein's theory of gravity is not quite right and that is something we will explore.