Linking theory with experiment: searches for new light particles

尽管粒子物理学的标准模型取得了许多惊人的成功，但它在最基本的层面上支撑着我们对宇宙的描述，远未完成。它最戏剧性的缺陷之一是无法解释暗物质。暗物质是一种新形式的物质，对于解释天体物理学和宇宙学观测是必要的，但从未被直接探测到，尽管它占宇宙质量的五倍于普通物质。在这个奖学金，我将解决具有挑战性的开放的理论问题，是至关重要的暗物质的实验研究，我将形成一个新的研究小组，作为一个桥梁，从理论到并行的主要英国和国际实验计划。这样做将使实验努力和投资的物理回报最大化。它还将为新仪器的开发提供重要的投入，大大增加革命性实验发现的可能性。构成暗物质的最重要候选者之一是新的轻粒子，因为这种粒子自然地出现在许多理论模型中;在早期宇宙中自动产生，可以解释标准模型的其他奥秘。为了表现出暗物质的行为，新的光粒子必须非常弱地耦合到可见部分，这使得它们的发现具有挑战性。然而，最近的技术进步，例如量子放大器，意味着现在可以寻找这些新的光粒子。因此，在英国和国际上，越来越多的实验努力旨在检测它们。然而，这样的研究面临着许多挑战：例如，一个新的轻粒子的质量可以跨越20多个数量级的范围，而任何一种仪器只能针对非常有限的质量。通过研究早期宇宙中新的轻粒子的动力学，我将预测暗物质的质量。这将通过提供精确的质量预测来极大地帮助实验工作，从而可以开发仪器来瞄准。我还将从恒星的观测中计算出对这些粒子的补充约束，以确保实验的设计对尚未排除的参数空间部分敏感。此外，我将通过了解这些粒子与普通物质相互作用的方式，以及包括寻找引力波在内的互补信号，研究潜在的新探测路线。我的研究将有利于理论物理和实验工作。通过了解新的轻粒子的性质，来自实验的约束可以用来最终排除理论模型。在最令人兴奋的发现场景中，这样的工作将被证明是非常宝贵的，可以确定已经发现了什么，以及这对我们理解宇宙意味着什么。例如，在一个特定的质量范围内的发现可以告诉我们宇宙在极早期的演化，当它处于一个能量高于任何我们可以直接研究。我提出的工作的一个独特的方面是计划直接链接到研究人员开发一个新的英国为基础的实验设施寻找暗物质。我提出的工作将加强和进一步激励这些努力，它将导致从理论物理到量子设备的设计和生产的所有联系。在这样做的过程中，它有可能彻底改变我们对宇宙基本性质的理解，并大大加强一个将导致重大技术发展和副产品应用的计划。

Despite its numerous spectacular successes, the standard model of particle physics, which underpins our description of the Universe at its most fundamental level, is far from complete. One of its most dramatic failings is its inability to account for dark matter. Dark matter is a new form of matter that is necessary to explain astrophysical and cosmological observations, but which has never been directly detected, despite accounting for five times as much of the Universe's mass as ordinary matter does. In this fellowship I will resolve challenging open theoretical questions that are crucial for the experimental search for dark matter, and I will form a new research group that acts as a bridge from theory to a concurrent major UK and international experimental programme. Doing so will maximise the physics returns from experimental efforts and investment. It will also provide vital input that will feed into the development of new instruments, substantially increasing the probability of a revolutionary experimental discovery.One of the foremost candidates to comprise dark matter is a new light particle, since such particles naturally appear in many theoretical models; are automatically produced in the early universe and can explain other mysteries of the standard model. To behave as dark matter new light particles must couple to the visible sector extremely weakly, which makes their discovery challenging. Nevertheless, recent technological advances, for example in quantum amplifiers, mean that these new light particles can now be searched for. Consequently, there is a growing experimental effort aimed at their detection, both in the UK and internationally. However, such searches face numerous challenges: for example, a new light particle could have a mass anywhere in a range that spans more than twenty orders of magnitude, whereas any one instrument can only target a very limited set of masses.By studying the dynamics of new light particles in the early universe I will make predictions for the dark matter mass. This will dramatically aid the experimental effort by providing sharp mass predictions that instruments can be developed to target. I will also calculate complementary constraints on such particles from observations of stars, to ensure that the experiments are designed to be sensitive to parts of parameter space that are not already ruled out. Further, I will investigate potential new routes to detection by understanding the way that such particles interact with ordinary matter, and complementary signals including in searches for gravitational waves.My research will benefit theoretical physics as well as the experimental effort. By understanding the properties of new light particles, constraints from experiments can be used to conclusively rule out theoretical models. In the most exciting scenario of a discovery, such work will prove invaluable in determining what has been found and what this means for our understanding of the Universe. For example, a discovery in a specific mass range could tell us about the Universe's evolution at extremely early times, when it was at an energy higher than any we could ever directly study.A unique aspect of my proposed work is the planned direct links to researchers developing a new UK based experimental facility searching for dark matter. My proposed work will strengthen and further motivate these efforts, and it will lead to connections all the way from theoretical physics to the design and production of quantum devices. In doing so it has the potential to both revolutionise our understanding of fundamental nature of the Universe, and to substantially strengthen a programme that will lead to significant technological development and spinoff applications.