Seminarium KMMF "Teoria Dwoistości"

In four-dimensional Euclidean Yang-Mills theory, I prove that correlation functions of arbitrary composite local operators exist to arbitrary order in perturbation theory, and fulfill the required Ward identities. The proof uses the framework of renormalisation group flow equations, coupled with the BRST method for gauge theories. The main ingredient are bounds formulated in terms of certain tree structures, which are precise enough to treat rigorously all UV and IR problems as well as gauge invariance. Joint work with J. Holland and S. Hollands, based on arXiv:1511.09425.