Luigi Bresciani, "All-Order Helicity Selection Rules in EFTs"

Thursday 22 Oct 2026, 13:30 → 14:30 Europe/Zurich

4/2-037 - TH meeting room (CERN)

On-shell methods provide a powerful framework for uncovering general patterns in the renormalization of EFTs. In this talk, I will present an all-order non-renormalization theorem for general four-dimensional EFTs, derived from Poincaré invariance and unitarity. The theorem identifies classes of operator mixing that must vanish at a given loop order, based entirely on tree-level information. These zeros are also robust under finite renormalizations, provided the operator-length selection rule is preserved. Applying the theorem to operators of dimensions five through eight, we uncover broad classes of previously unknown non-renormalization patterns, with particular emphasis on two loops. Finally, I will discuss how these results provide useful consistency checks for existing and future anomalous-dimension calculations, including those in the SMEFT.