Gauge Dynamics and Physics Beyond the Standard Model

现代粒子物理学面临着一幅矛盾的图景。一方面，实验数据导致了对“标准模型”（SM）的非常精确的验证，最终在2012年大型强子对撞机发现了一个类似标准模型的希格斯玻色子。另一方面，观测宇宙学在数量上的巨大进步表明，尽管它取得了成功，但在宇宙尺度上仍有很多东西无法解释，最突出的是暗物质。这一经验难题，结合了对SM的各种更理论化的关注，激发了在多个方向上进一步的理论工作：在寻找新物理迹象的过程中分析广泛的渠道；同时更深入地探索SM的主要结构，以更好地理解它的成功。我的研究计划的目标是由这种双重视角驱动的。

Modern particle physics faces a conflicted picture. On one hand, experimental data has led to a remarkably precise verification of the `Standard Model' (SM), culminating in the LHC's discovery of a SM-like Higgs boson in 2012. On the other hand, tremendous quantitative advances in observational cosmology show that, despite its success, there is much that the SM cannot explain on cosmological scales, most prominently dark matter. This empirical puzzle, combined with various more theoretical concerns about the SM, motivates further theoretical work in multiple directions: to analyze a wide range of channels in the search for signs of new physics; and at the same time to explore the primary structures of the SM in greater depth, to better understand its success. The objectives of my research proposal are motivated by this dual perspective. Progress in our understanding of gauge field theories, the building blocks of the SM, is important at both a foundational level, and also for developing new calculational tools to describe the behaviour of matter in extreme regimes. One aspect of the proposed research focuses on the real-time dynamical behaviour of gauge theories at finite temperature, which near equilibrium can be described using hydrodynamics. A goal is to better understand the connections between these two approaches, by combining the tools of quantum field theory with new holographic methods, which have emerged from string theory. This has a range of possible applications, but an important (motivating) scenario is the strongly-interacting dynamics of QCD (the gauge theory of the strong nuclear interactions), in regimes that are explored in experiments such as RHIC and the LHC which collide heavy ions. The second strand of my proposal is more data-driven and aims to study scenarios and detection channels for empirically motivated physics beyond the Standard Model, such as dark matter. The emphasis is on the use of systematic effective field theory techniques to fully exploit high precision and high luminosity experiments, which are often indirectly sensitive to a much wider range of energy scales than are directly achievable at high energy colliders. The primary questions to be addressed include, what mechanism determines the relic asymmetry between matter and antimatter in the universe (which requires new "CP-violating" interactions); and also how best to probe the identity of dark matter, either directly in underground labs, using medium-energy fixed-target experiments and colliders, or indirectly through observations of cosmology, the galaxy, and stellar physics.