29 July 2019 to 2 August 2019
Northeastern University
US/Eastern timezone

The Four-Fermi Interaction in the Standard Model Effective Theory

30 Jul 2019, 17:42
Shillman 335 (Northeastern University)

Shillman 335

Northeastern University

Oral Presentation Beyond Standard Model Physics Beyond Standard Model


Dr Daniel Wiegand (Northwestern University/ANL)


The Standard Model Effective Theory (SMEFT) is a powerful tool to constrain physics beyond the Standard Model through data, without making restricting assumptions about the nature of the UV theory.
Even though there has been a lot of work put into constraining many of the dimension 6 operators, the large subset of four-Fermi operators has been wildly neglected in NLO analysis, due to SMEFT being a non-classically renormalizable theory. We present an investigation into the treatment of the renormalization procedure in combination with dimensional regularization and specifically a recipe how to treat \gamma_5 in a self-consistent way, while preserving all relevant Ward identities.
Furthermore, as an application of our newly compiled techniques, we present bounds on a number of four-Fermi Wilson coefficients derived through considering Top quark decay helicity fractions as well comparing well-measured low energy observables (namely Z boson partial widths and the effective weak mixing angle) to their SMEFT predictions.

Primary author

Dr Daniel Wiegand (Northwestern University/ANL)


Radja Boughezal (Argonne National Laboratory) Frank Petriello (Northwestern University and Argonne National Lab)

Presentation Materials