The CKM parameters in the SMEFT

Understand

The extraction of the Cabibbo-Kobayashi-Maskawa (CKM) matrix from flavour observables can be affected by physics beyond the Standard Model (SM).

• We provide a general roadmap to take this into account, which we apply to the case of the Standard Model Effective Field Theory (SMEFT).
• We choose a set of four input observables that determine the four Wolfenstein parameters, and discuss how the effects of dimension-six operators can be included in their definition.
• We provide numerical values and confidence intervals for the CKM parameters, and compare them with the results of CKM fits obtained in the SM context.