Fermionic gradient flow in combination with the short flow time expansion provides a renormalisation scheme where hadronic matrix elements on the lattice are evolved along the flow time gradually removing UV divergences.
In this renormalisation scheme certain challenges such as mixing with operators of lower mass dimension are suppressed or shifted to the perturbative part of the procedure,...
Non-perturbative matrix elements of four-quark operators are essential ingredients for the determination of heavy meson lifetimes. The gradient flow formalism provides a way for their calculation in lattice gauge theory. This requires the knowledge of the coefficients of the short-flow-time expansion of the corresponding operators, which can be calculated in perturbation theory. In this talk,...
