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arXiv · 2407.18185

On the two-loop BSM corrections to $h\longrightarrow \gamma\gamma$ in a triplet extension of the SM

Giuseppe Degrassi·Pietro Slavich
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Abstract

We compute the two-loop BSM contributions to the $h\longrightarrow \gamma\gamma$ decay width in the SM extended with a real triplet of $SU(2)$. We consider scenarios in which the neutral components of doublet and triplet do not mix, so that the lighter neutral scalar $h$ has (at least approximately) SM-like couplings to fermions and gauge bosons. We focus on the two-loop corrections controlled by the quartic scalar couplings, and obtain explicit and compact formulas for the $h \gamma \gamma$ amplitude by means of a low-energy theorem that connects it to the derivative of the photon self-energy w.r.t. the Higgs field. We briefly discuss the numerical impact of the newly-computed contributions, showing that they may be required for a precise determination of $\Gamma[h\rightarrow \gamma \gamma]$ in scenarios where the quartic scalar couplings are large.

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Giuseppe Degrassi, Pietro Slavich. 2024-07-25. On the two-loop BSM corrections to $h\longrightarrow \gamma\gamma$ in a triplet extension of the SM. https://arxiv.org/abs/2407.18185

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