Ludvig Chen, Matching EFTs on-shell

Wednesday 19 Nov 2025, 13:30 → 14:30 Europe/Stockholm

Å92110 (Ångströmslaboratoriet)

I will discuss an on-shell method of matching a UV theory onto its low energy EFT via a complex momentum dilatation, based on 2308.00035. The matching is done through a dispersion relation, which allows one to extract EFT parameters purely from the analytic structure of the UV amplitude. In particular, one-loop matching can be obtained using only tree-level inputs. Moreover, contributions to all EFT orders can be obtained at once and it bypasses the need to specify an operator basis for the EFT. This approach could help improve our understanding of positivity bounds and connects to the broader program of understanding how the UV theory constrains the EFT parameter space.