Linking theory with experiment: searches for new light particles

尽管它取得了许多惊人的成功，但支撑我们在最基本层面上描述宇宙的粒子物理学标准模型还远未完成。它最戏剧性的缺陷之一是它无法解释暗物质。暗物质是一种新的物质形式，对于解释天体物理和宇宙学观察是必要的，但它从未被直接探测到，尽管它占宇宙质量的五倍于普通物质。在这一奖学金中，我将解决对暗物质的实验搜索至关重要的具有挑战性的开放理论问题，并将成立一个新的研究小组，充当从理论到同时进行的英国和国际重大实验计划的桥梁。这样做将最大化从实验努力和投资中获得的物理学回报。它还将为新仪器的发展提供重要的输入，大大增加革命性实验发现的可能性。组成暗物质的最可能的候选之一是一种新的轻粒子，因为这种粒子自然出现在许多理论模型中；这种粒子是在早期宇宙中自动产生的，可以解释标准模型的其他谜团。要表现为暗物质，新的光粒子必须极弱地耦合到可见光部分，这使得它们的发现具有挑战性。然而，最近的技术进步，例如在量子放大器方面，意味着现在可以搜索这些新的轻粒子。因此，无论是在英国还是在国际上，都有越来越多的实验努力旨在检测它们。然而，这样的搜索面临着许多挑战：例如，一个新的轻粒子的质量可能在超过20个数量级的范围内的任何地方，而任何一台仪器只能瞄准非常有限的一组质量。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。这将极大地帮助实验工作，因为它提供了准确的质量预测，使仪器可以被开发成目标。我还将根据对恒星的观测来计算对这类粒子的互补约束，以确保实验被设计为对尚未排除的参数空间的部分敏感。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，来研究潜在的新探测途径。我的研究将有助于理论物理和实验工作。通过了解新的轻粒子的性质，来自实验的限制可以用来最终排除理论模型。在最令人兴奋的发现情景中，这些工作将被证明是无价的，可以确定发现了什么，以及这对我们对宇宙的理解意味着什么。例如，在特定质量范围内的一项发现可以告诉我们宇宙在极早期的演化，当时宇宙的能量比我们可以直接研究的任何东西都要高。我提议的工作的一个独特方面是计划直接链接到研究人员开发一个新的英国实验设备来搜索暗物质。我提议的工作将加强并进一步推动这些努力，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。通过这样做，它有可能彻底改变我们对宇宙根本性质的理解，并极大地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.