Triple Higgs coupling effect on $h^0\to b\bar{b}$ and $h^0\to {\tau }^{+}{\tau }^{-}$ in the 2HDM

Abstract

We study the one loop electroweak radiative corrections to $h^0\to b\bar{b}$ and $h^0\to {\tau }^{+}{\tau }^{-}$ in the framework of two Higgs doublet Model (2HDM). We evaluate the deviation of these couplings from their Standard Model (SM) values. $h^0\to b\bar{b}$ and $h^0\to {\tau }^{+}{\tau }^{-}$ may receives large contribution from triple couplings $h^0{H}^0{H}^0$, $H^0{h}^0{h}^0$, $h^0{A}^0{A}^0$ and $h^0{H}^{+}{H}^{-}$ which are absent in the Standard Model. It is found that in 2HDM, these corrections could be significant and may reach more than 20\% for not tow heavy $H^0$ or $A^0$ or $H^{\pm }$. We also study the ratio of branching ratios $R=BR(h^0\to b\bar{b})/BR(h^0\to {\tau }^{+}{\tau }^{-})$ of Higgs boson decays which could be used to disentangle SM from other models such as 2HDM.

Comments: 18 pages, 6 figures, typos corrected, references added