Quantum Fields and Physics Beyond the Standard Model

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Modern particle physics faces a conflicted picture. On one hand, experimental data has led to a remarkably precise verification of the `Standard Model' (SM), including the discovery of the Higgs boson at the Large Hadron Collider (LHC) 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. Such empirical puzzles, combined with other structural questions about the SM, motivate further theoretical work in multiple directions: to analyze a wide range of channels in search of new physics; and at the same time to explore and the primary structures of the SM in greater depth, to better understand its success and develop applications to new regimes. This dual perspective drives my two long-term research goals. The first long term goal is to better understand the origin of the matter content in the universe. My current focus is on scenarios and detection channels for empirically motivated physics beyond the Standard Model, specifically dark matter. Evidence points to a framework in which dark matter is part of a hidden (or dark) sector, weakly coupled to the SM. Research objectives include the use of systematic effective field theory techniques to 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. Questions to be addressed include how to explore the viable parameter space of low mass dark matter candidates, either directly in underground labs, using medium-energy fixed-target experiments and colliders, or indirectly through observations of cosmology, the galaxy, and stellar physics; and what mechanism determines the relic asymmetry between matter and antimatter in the universe (which requires new "CP-violating" interactions). The second long term goal of this program aims to further our understanding of quantum (gauge) field theories, the building blocks of the SM. This is important at both a foundational level, and also for developing new calculational tools to describe matter in thermal or non-equilibrium regimes. One aspect of the proposed research focuses on the real-time dynamical behaviour of field theories at finite temperature, which near equilibrium can be described using hydrodynamics. A specific objective is to develop the field theoretic understanding of the hydrodynamic regime, using the tools of effective quantum field theory. This has a range of potential 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.