Speaker
Description
Understanding coupled-channel dynamics involving three or more particles remains a major challenge for computing hadronic scattering and decay processes on the lattice. We present a perturbative framework for describing such systems involving an arbitrary number of particles in a finite volume. Our method is valid at leading order in all $n\to m$ couplings of the theory, and incorporates the finite-volume effects associated with leading-order subprocesses in every sector with three or more particles. We present the resulting quantisation condition and discuss its domain of validity. We also discuss an extension to a hybrid formalism that combines a non-perturbative treatment of two-particle dynamics with a perturbative treatment of sectors containing three or more particles. Finally, we outline potential applications to multi-hadron processes relevant to lattice QCD.