DARK MAtter for Precision experiments (DARKMAP)

我们对宇宙内部运作的最好理解要求暗物质贡献大约宇宙总质量的80%，在所有天文尺度上塑造它的形态。然而，从基本粒子的角度来看，暗物质的组成仍然是一个谜，所有通过测量或直接观测来解决这个问题的尝试都以失败告终。已经建立的实验专注于寻找在地下深处实验室中散布出重原子的暗物质，假设它的行为像缓慢移动的粒子。这种类型的暗物质被称为弱相互作用大质量粒子(WIMP)，其质量是质子质量的倍数。对于低于碳原子质量的暗物质质量，缓慢移动的WIMP的动量降至这些实验中使用的重原子核的反冲阈值以下，因此无法再检测到它。如果暗物质要轻得多，它的性质就会有根本的不同，它应该被描述为一种均匀的类似流体的物质，而不是一团巨大的粒子云。在这种情况下，寻找弹性散射的实验是完全不敏感的。这种非常轻的暗物质的行为更像是一种新的力量，作用在电子和原子核上，非常微弱，或者影响它们的自旋。在这种情况下，预期的影响是微小的，只有在对基本常量和相互作用的极其精确的测量中才能观察到。这个项目是一个真正的多学科努力，能够通过高精度的原子物理实验来搜索暗物质。在过去的几十年里，这些实验中的许多都取得了巨大的进步，它们的灵敏度提高了许多数量级。这些高精度的实验可能会测量光和非常亮的暗物质相互作用所产生的微小影响。宇宙中产生这种暗物质的理论机制是有帮助的，因为它预测到，如果实验可以被设计成能够捕捉到这种暗物质，它可以共振地增强依赖时间的信号。根据具体的相互作用，一个专门的或各种实验可能是正确的策略。为了回答这个问题，将建立一个一致的理论框架，考虑到描述高能暗物质所需的量子场论的复杂结构。尽管与对撞机实验甚至某些天体物理过程相比，高精度实验是在相当低的能量下进行的，但这些计算对于正确地推导这些实验的可观测性和可观测性之间的关联是必要的。这一框架进一步使不同的实验方法具有可比性，现有的限制可以用于优化未来的实验。有了这一点，我们可以与英国各地的原子物理学家合作，设计一个实验计划，利用尚未开发的高精度实验的潜力来搜索和潜在地发现暗物质。

Our best understanding of the inner working of the Universe demands that Dark Matter contributes about 80% of the total mass of the Universe, shaping its form at all astronomical scales. However, the composition of Dark Matter in terms of fundamental particles remains a puzzleand all attempts to solve it through measurements or direct observation have failed to date.Established experiments have focussed on searches for Dark Matter that scatters off heavy atoms in deep underground labs, assuming it behaves like slowly moving particles. This type of Dark Matter is called Weakly Interacting Massive Particle (WIMP) and its mass is a multiple of the proton mass. For Dark Matter masses below the mass of a Carbon atom the momentum of the slowly moving WIMPs drops below the recoil threshold of the heavy nuclei used in these experiments and it cannot be detected anymore. If Dark Matter is much lighter, its properties are fundamentally different, and it would be better described as a homogeneous fluid-like substance instead of a cloud of massive particle. Experiments searching for elastic scattering are entirely insensitive in this case. This very light Dark Matter behaves more like a new force acting very weakly on electrons and nuclei or affecting their spin. In this case the expected effects are tiny and can only be observed in extremely precise measurements of fundamental constants and interactions.This project is a truly multidisciplinary effort to enable the search for dark matter with high-precision atomic physics experiments. Many of these experiments have made enormous progress during the last decades, increasing their sensitivity by many orders of magnitude. These high-precision experiments can potentially measure the very minute effects exerted by interactions of light and very light dark matter. The theoretical mechanism underlying the production of this type of dark matter in the universe helps, because it predicts resonantly enhanced time-dependent signals, if the experiment can be designed to pick it up. Depending on the specific interaction, one dedicated or a variety of experiments might be the right strategy.In order to answer this question a consistent theoretical framework will be developed taking into account the complex structure of quantum field theories necessary to describe dark matter at high energies. Even though high-precision experiments are performed at rather low energies compared to collider experiments or even some astrophysical processes these calculations are necessary to correctly derive observables and correlations between observables for these experiments. This framework further makes the different experimental approaches comparable and existing limits can be used to optimise future experiments. With this in hand we can collaborate with atomic physicists throughout the UK to design an experimental programme exploiting the untapped potential of high-precision experiments to search for and potentially discover dark matter.