SMEFT interpretation of single top quark and Z boson (tZq) production at the ATLAS experiment

Although the Standard Model (SM) of particle physics has successfully explained observed phenomena, there are hints of new physics beyond the SM, such as dark matter and neutrino oscillations and masses. The Standard Model Effective Field Theory (SMEFT) provides a framework for parametrizing high-energy phenomena by incorporating additional operators in the Lagrangian with dimensions larger than those in the SM. These operators form a basis describing all possible interactions and couplings where new physics can hide.

Single top quark and Z boson production is an ideal process for performing EFT interpretations because it involves couplings of the top quark with W and Z bosons, making it sensitive to several SMEFT operators. In this analysis, kinematic distributions at the detector level are used to constrain the Wilson coefficients of dimension-six operators to which the tZq channel is sensitive, via profile likelihood fits. The constraints obtained through this detector-level approach and the efforts to optimize the EFT-sensitive regions will be presented in this talk.