The CKM parameters in the SMEFT

• Main Authors: Sébastien Descotes-Genon, Adam Falkowski, Marco Fedele, Martín González-Alonso, Javier Virto
• Format: Article
• Language: English
• Published: SpringerOpen 2019-05-01
• Series: Journal of High Energy Physics
• Subjects: Beyond Standard Model; Effective Field Theories; Quark Masses and SM Parameters
• Online Access: http://link.springer.com/article/10.1007/JHEP05(2019)172

Abstract 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. Our approach allows one to perform general SMEFT analyses in a consistent fashion, independently of any assumptions about the way new physics affects flavour observables. We discuss a few examples illustrating how our approach can be implemented in practice.