# $\mu \rightarrow e \gamma$ μ → e γ in the 2HDM: an exercise in EFT

Abstract : The 2 Higgs Doublet Model (2HDM) of type III has renormalisable Lepton Flavour-Violating couplings, and its one and two-loop ("Barr-Zee") contributions to $\mu \to e \gamma$ are known. In the decoupling limit, where the mass scale M of the second doublet is much greater than the electroweak scale, the model can be parametrised with an Effective Field Theory(EFT) containing dimension six operators. The $1/M^2$ terms of the exact calculation are reproduced in the EFT, provided that the four-fermion operator basis below the weak scale is enlarged with respect to the SU(2)-invariant Buchmuller-Wyler list. The two-loop "Barr-Zee" contributions are located in the EFT, showing that two-loop matching and running would be required to obtain the most important contributions, and that dimension eight operators can be numerically relevant.
Document type :
Journal articles

http://hal.in2p3.fr/in2p3-01255884
Contributor : Sylvie Flores <>
Submitted on : Thursday, January 14, 2016 - 10:05:32 AM
Last modification on : Thursday, March 15, 2018 - 11:40:10 AM

### Citation

S. Davidson. $\mu \rightarrow e \gamma$ μ → e γ in the 2HDM: an exercise in EFT. European Physical Journal C: Particles and Fields, Springer Verlag (Germany), 2016, 76 (5), pp.258. ⟨10.1140/epjc/s10052-016-4076-y⟩. ⟨in2p3-01255884⟩

Record views