Probing the flavour-blind SMEFT: EFT validity and the interplay of energy scales

• Published in: The journal of high energy physics Vol. 2025; no. 6; pp. 147 - 31
• Main Authors: Mantani, Luca, Sanz, Veronica
• Format: Journal Article
• Language: English
• Published: Berlin/Heidelberg Springer Berlin Heidelberg 01.06.2025; Springer Nature B.V; SpringerOpen
• Subjects: Classical and Quantum Gravitation; Datasets; Electroweak Precision Physics; Elementary Particles; Energy; Field theory; Flavors; Kinematics; Large Hadron Collider; Parameter sensitivity; Particle decay; Physics; Physics and Astronomy; Quantum Field Theories; Quantum Field Theory; Quantum Physics; Rare Decays; Regular Article - Theoretical Physics; Relativity Theory; SMEFT; Standard model (particle physics); String Theory; Rare Decays; SMEFT; Electroweak Precision Physics
• ISSN: 1029-8479; 1029-8479
• DOI: 10.1007/JHEP06(2025)147

A bstract The Standard Model Effective Field Theory (SMEFT) offers a systematic approach to study potential deviations from the Standard Model (SM) through higher-dimensional operators that encapsulate new physics effects. In this work, we analyze flavour-blind SMEFT contributions to flavour observables and assess their interplay with high-energy measurements from LEP and LHC. We perform global fits combining LEP precision data, flavour observables from rare B-meson decays, and LHC diboson measurements, revealing how the inclusion of different datasets breaks parameter degeneracies and enhances the sensitivity to SMEFT coefficients. Our study demonstrates that low-energy flavour observables provide reliable constraints even in flavour-blind scenarios, while high-energy measurements can be subject to EFT validity concerns due to kinematic growth. We investigate the impact of renormalization group evolution (RGE) and operator mixing across energy scales, highlighting the complementary nature of low- and high-energy datasets. The results emphasize the importance of flavour observables as robust probes of new physics and underline the necessity of global fits to avoid potential biases from limited datasets. Finally, we discuss the implications of our findings for the interpretation of global SMEFT analyses based on high-energy collider data, comparing UV models that contribute to SMEFT at tree- and loop-level.