CP-Violation in a composite 2-Higgs doublet model

Stefania De Curtis,Ryo Nagai,Stefano Moretti,Kei Yagyu

doi:10.1007/jhep10(2021)040

Stefania De Curtis, Ryo Nagai + Show 2 more

Open Access

https://doi.org/10.1007/jhep10(2021)040

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Abstract

We study CP-Violation (CPV) in a Composite 2-Higgs Doublet Model (C2HDM) based on the global symmetry breaking SO(6)/[SO(4) × SO(2)], wherein the strong sector is modeled by a two-site moose structure. Non-trivial complex phases in the interactions involving fermions in both the elementary and strong sectors can induce CPV in the Higgs potential as well as the Yukawa coupling parameters. We compute both of the latter and analyse their dependence upon the aforementioned complex phases. Finally, we discuss physics observables which are distinctive of this model. Even in the simplest case with only one complex phase in the strong sector we can get significant CPV effects.

Highlights

We study CP-Violation (CPV) in a Composite 2-Higgs Doublet Model (C2HDM) based on the global symmetry breaking SO(6)/[SO(4) × SO(2)], wherein the strong sector is modeled by a two-site moose structure
We have studied a CHM based on the global symmetry breaking SO(6) → SO(4) × SO(2), paying particular attention to CPV generated in the strong sector
The 8 pNGBs that emerge from such a dynamics behave as two SU(2) doublet Higgs fields and their properties are determined by the strong dynamics behind the aforementioned breaking

Summary

The Higgs potential and top Yukawa sector

We have introduced the SM gauge bosons and fermions in the elementary sector. Since the embedding of the SM fields explicitly breaks the shift symmetry, the SM field interactions. If the Higgs potential contains a physical CPV phase, these three neutral Higgs bosons φ01,2,3 are mixed with each other Their mass eigenstates (h1, h2, h3) are defined by introducing a 3 × 3 orthogonal matrix R as φ01. (This is a rather generic aspect in CHMs with CPV.) Secondly, the C2HDM with CPV generally predicts spontaneous CPV, contrarily to the E2HDM case, where both Higgs VEVs can be taken to be real and positive (without loss of generality) by rephasing the Higgs fields and redefining the potential parameters, which is not allowed in our case, so that the relative phase of the two VEVs, θv, must be retained.

M2 3 f3

Signatures of the C2HDM with CPV

Summary and conclusions

A Fermion form factors with CPV

B Higgs potential parameters