Mia West, KIT, [HET Seminar] An Isotropic Prescription for Constructing the SMEFT in Normal Coordinates to Simplify Amplitude Computations

Thursday 18 Jun 2026, 11:00 → 13:00 US/Eastern

Small Seminar Room

Geometry provides us with a convenient interpretation of field-redefinition invariance for amplitudes and has many useful properties. For instance, it directs us towards Riemann Normal Coordinates (RNC) as an ideal choice of field-redefinition to compute amplitudes.

It has been shown in the Higgs Effective Field Theory (HEFT) assuming custodial symmetry and in the high-energy limit in RNC there are distinct kinematics for each Feynman graph. Redefining the Lagrangian in these coordinates appears to generate a reduced set of Feynman graphs which still sum to the correct amplitude. This property also holds in the Standard Model EFT (SMEFT) as a subset of HEFT.

In this talk, we will demonstrate a prescription to construct the SMEFT in RNC around the symmetric point using isotropy, applicable to all orders in the SMEFT expansion. Then, breaking electroweak symmetry corresponds to traversing a geodesic to the vacuum and re-establishing RNC in terms of isotropic properties of the symmetric point. We argue that this prescription is simpler compared to the usual recursive method to construct RNC.

 

https://bnl.zoomgov.com/j/16010362754?pwd=Z1l1SS9JUDlyR1hSUHNyaDV1dTZHUT09