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Physical Review D 100, 075014 (2019)


Neutral Higgs boson decays H → Zγ,γγ in 3-3-1 models

H. T. Hung, T. T. Hong, H. H. Phuong, H. L. T. Mai, and L. T. Hue

The significance of new physics appearing in the loop-induced decays of neutral Higgs bosons into pairs of dibosons γγ and Zγ will be discussed in the framework of the 3-3-1 models based on a recent work [H. Okada, N. Okada, Y. Orikasa, and K. Yagyu, Phys. Rev. D 94, 015002 (2016)], where the Higgs sector becomes effectively the same as that in the two Higgs doublet models (2HDM) after the first symmetry breaking from SU(3)_L scale into the electroweak scale. For large SU(3)_L scale v3 ≃ 10 TeV, dominant one-loop contributions to the two decay amplitudes arise from only the single charged Higgs boson predicted by the 2HDM, leading to that experimental constraint on the signal strength (μ^331)_γγ of the Standard Model-like Higgs boson decay h → γγ will result in a strict upper bound on the signal strength (μ^331)_ Zγ of the decay h → Zγ. For a particular model with lower v3 around 3 TeV, contributions from heavy charged gauge and Higgs bosons may have the same order, therefore may give strong destructive or constructive correlations. As a by-product, a deviation from the SM prediction $(μ^331)_γγ − 1$ ≤ 0.04 still allows $(μ^331)_Zγ − 1$ to reach values near 0.1. We also show that there exists an CP-even neutral Higgs boson (h^0)_3 predicted by the 3-3-1 models, but beyond the 2HDM, has an interesting property that the branching ratio Br((h^0)_3 → γγ) is very sensitive to the parameter β used to distinguish different 3-3-1 models.

DOI: 10.1103/PhysRevD.100.075014