A number of outstanding open challenges at the frontier of particle physics are related to nonrelativistic bound (NR) systems, characterized by the existence of a pattern of separated energy scales. Effective Quantum Field Theory Methods (EFTs) have been very impactful, allowing systematic and precise determinations of processes at high energy collider experiments (LHC at CERN, RHIC at BNL, BELLE II at KEK, BESIII at IHEP and Jlab).
In this colloquium I will address the current frontier i.e. the study of NR bound states in complex environments, like states above the strong decay threshold or out-of-equilibrium in a hot medium. Understanding the behaviour of these systems is crucial for our progress in the physics of the Standard Model and beyond. Examples will include the exotic X, Y, Z states, Quarkonium production at high energy colliders, the evolution of quarkonia in the hot medium created in heavy-ion collisions, thermal production of heavy particles and dark matter in the primordial plasma.
In particular I will discuss how our ability to do precision calculations and to control strongly interacting systems is related to developing the interface of perturbative calculations with nonperturbative tools, notably numerical lattice gauge theories.