Exploring Dimuon Higgs Decay in an Extended Scotogenic Model

We investigate the dimuon Higgs decay $h \to \mu^+\mu^-$ in the context of an extended Scotogenic model. The model introduces a singlet complex scalar in addition to the standard Scotogenic scalar doublet and singlet fermions, charged under a dark $\mathbb{Z}_2$ symmetry. By exploring the one-loop contributions, we show that the model allows for sizable deviations in the Higgs dimuon decay rate, quantified by the quotient $R_{\mu\mu} = \text{Br}(h \to \mu^+\mu^-)/\text{Br}(h \to \mu^+\mu^-)_{\text{SM}}$. Crucially, these deviations comply with experimental limits, including those on $\text{Br}(\mu^{+} \to e^{+}\gamma)$ and $\text{Br}(h \to \gamma\gamma)$. Such deviations can be tested and constrained by future precision measurements at the LHC.