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arXiv · 1304.3689

Enhancement of H -> gamma gamma in SU(5) model with 45_H plet

S. Khalil·S. Salem
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Abstract

We show that the low energy effective model derived from SU(5) with 45-plet Higgs can account for the recently reported enhanced diphoton decay rate of the Standard Model (SM)-like Higgs with mass about 125 GeV. This model extends the SM by an extra Higgs doublet and color-octet scalar doublet. We show that the charged octet scalars are not severely constrained by flavor changing neutral current and can be light. However, the K^0-\bar{K}^0 mixing implies that the neutral octet-scalar mass should be larger than 400 GeV for \tanβ~ O(1). The role of charged octet scalar in the loop of Higgs decay into diphoton is investigated . We point out that the most significant impact of this model on the diphoton decay width comes from the suppression of top-quark coupling with SM-like Higgs or even flipping its sign that leads to important enhancement in Γ(h -> gamma gamma). We also study the implications of the neutral octet-scalar contributions to the gluon fusion Higgs production cross section in alleviating the apparent tension between enhancement of diphoton decay rate and suppression of σ(gg -> h).

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S. Khalil, S. Salem. 2013-04-12. Enhancement of H -> gamma gamma in SU(5) model with 45_H plet. https://doi.org/10.1016/j.nuclphysb.2013.08.016

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