EFT approach in U(2) and U(3) flavor symmetries

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Overview

The measurements of quark flavor-violating observables show a success of the Standard Model (SM). If we insist that new physics (NP) has to emerge in the TeV region, we need to conclude that NP possesses a highly non-generic flavor structure (flavor problem). One of the reasonable solutions to the flavor problem is to introduce flavor symmetry hypothesis. U(3) flavor symmetry is the maximal flavor symmetry allowed by the SM gauge group, and it is known as the Minimal Flavor Violation hypothesis. U(2) is the corresponding subgroup acting only on the first two (light) generations, and shows a good agreement with Yukawa and CKM hierarchical structures. Interestingly, it is shown that U(2) has a good compatibility with the recent B-anomalies. On the other hand, LHC results so far show that there is a mass gap between the SM spectrum and NP. It has motivated the systematic Effective Field Theory (EFT) approach. In this talk, after a brief review of U(3) and U(2) flavor symmetry, I will show how these flavor symmetries act on the SMEFT, providing an organizing principle to classify the large number of dimension-six operators involving fermion fields. The phenomenological study focusing on B-anomalies will be also discussed.

References
JHEP 08 (2020) 166, e-Print: 2005.05366 [hep-ph]
Phys.Lett.B 800 (2020) 135080, e-Print: 1909.02519 [hep-ph]