On the two-loop BSM corrections to $$h\longrightarrow \gamma \gamma $$ in the aligned THDM
G. Degrassi, P. Slavich
Abstract
Abstract We compute the two-loop BSM contributions to the $$h\longrightarrow \gamma \gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mo>⟶</mml:mo> <mml:mi>γ</mml:mi> <mml:mi>γ</mml:mi> </mml:mrow> </mml:math> decay width in the aligned THDM. We adopt the simplifying assumptions of vanishing EW gauge couplings and vanishing mass of the SM-like Higgs boson, which allow us to exploit a low-energy theorem connecting the $$h\gamma \gamma $$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>h</mml:mi> <mml:mi>γ</mml:mi> <mml:mi>γ</mml:mi> </mml:mrow> </mml:math> amplitude 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 $$\Gamma [h\rightarrow \gamma \gamma ]$$ <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> <mml:mrow> <mml:mi>Γ</mml:mi> <mml:mo>[</mml:mo> <mml:mi>h</mml:mi> <mml:mo>→</mml:mo> <mml:mi>γ</mml:mi> <mml:mi>γ</mml:mi> <mml:mo>]</mml:mo> </mml:mrow> </mml:math> in scenarios where the quartic Higgs couplings are large.