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The one-loop contributions to the decays of the $CP$-odd and $CP$-even scalarbosons $A\to Z\gamma\gamma$ and $\phi\to Z\gamma\gamma$ ($\phi=h,H$) arecalculated within the framework of $CP$-conserving THDMs, where they areinduced by box and reducible Feynman diagrams. The behavior of thecorresponding branching ratios are then analyzed within the type-II THDM in aregion of the parameter space around the alignment limit and still consistentwith experimental data. It is found that the $A\to Z\gamma\gamma$ branchingratio is only relevant when $m_A>m_H+m_Z$, but it is negligible otherwise. For$m_A>600$ GeV and $t_\beta\simeq O(1)$, $BR(A\to Z\gamma\gamma)$ can reachvalues of the order of $10^{-5}-10^{-4}$, but it decreases by about one orderof magnitude as $t_\beta$ increases up to 10. A similar behavior is followed bythe $H\to Z\gamma\gamma$ decay, which only has a non-negligible branching ratiowhen $m_H>m_A+m_Z$ and can reach the level of $10^{-4}-10^{-3}$ for $m_H>600$GeV and $t_\beta\simeq O(1)$. We also estimated the branching ratios of theserare decays in the type-I THDM, where they can be about one order of magnitudelarger than in type-II THDM. As far as the $h\to Z\gamma\gamma$ decay isconcerned, since the properties of this scalar boson must be nearly identicalto those of the SM Higgs boson, the $h\to Z\gamma\gamma$ branching ratio doesnot deviates significantly from the SM prediction, where it is negligiblysmall, of the order of $10^{-9}$. This result is in agreement with previouscalculations.

Decays $A \to Z\gamma\gamma$ and $\phi \to Z\gamma\gamma$ ($\phi=h,H$) in two-Higgs doublet models