Large $h\to bs$ in generic two-Higgs-doublet models

Abstract

We investigate the possible size of $h\to bs$ in two-Higgs-doublet models with generic Yukawa couplings. Even though the corresponding rates are in general expected to be small due to the indirect constraints from $B_s\to {\mu }^{+}{\mu }^{-}$ and $B_s$--${\overline{B}}_s$ mixing, we find regions in parameter space where $h\to bs$ can have a sizable branching ratio well above 10\%. This requires a tuning of the neutral scalar masses and their couplings to muons, but then all additional constraints such as $B\to X_s\gamma$, $(g-2{)}_{\mu }$, and $h\to {\mu }^{+}{\mu }^{-}$ are satisfied. In this case, $h\to bs$ can be a relevant background in $h\to b\bar{b}$ searches and vice versa due to the imperfect $b$-tagging purity. Furthermore, if $h\to bs$ is sizeable, one expects two more scalar resonances in the proximity of $m_h$. We briefly comment on other flavour violating Higgs decays and on the 95 GeV $\gamma \gamma$ resonance within generic two-Higgs-doublet models.

Comments: 12 pages, 4 figures, 2 tables, version accepted for publication in PRD