Speaker
Description
Four-fermion interactions are important in many areas of particle physics, from effective descriptions of weak interactions and QCD to parametrisations of new physics in SMEFT or HEFT. In this talk I demonstrate that four-fermion interactions may develop strongly coupled UV fixed points in four dimensional QFTs. Contrary to weakly coupled expectations, their high energy limit may be (near-) conformal, with radically altered scaling behaviour due to large anomalous dimensions. The idea will be illustrated in a purely fermionic model of the Gross-Neveu type using the toolbox of the large-N expansion. I will show that the model, suitably extended with higher-derivative and eight-fermion interactions, is renormalisable to all orders in the expansion, with physical predictions being fully determined in terms of three parameters. I will further discuss exact RG running and operator scaling in the near-conformal UV regime, including from the perspective of functional renormalisation, as well as implications for effective theory and model building.
| Affiliation | University of Sussex & TU Dortmund |
|---|---|
| Link to paper | https://arxiv.org/abs/2603.19357 |
| Career status | Postdoc |