We study the constraints of the generic two-Higgs-doublet model (2HDM) type-III and the impacts of the new Yukawa couplings. For comparisons, we revisit the analysis in the 2HDM type-II. To understand the influence of all involving free parameters and to realize their correlations, we employ $chi$-square fitting approach by including theoretical and experimental constraints, such as S, T, and U oblique parameters, the production of standard model Higgs and its decay to $gammagamma$, $WW^*/ZZ^*$, $tau^+tau^-$, etc. The errors of analysis are taken at $68%$, $95.5%$, and $99.7%$ confidence levels. Due to the new Yukawa couplings being associated with $cos(beta-alpha)$ and $sin(beta -alpha)$, we find that the allowed regions for $sinalpha$ and $tanbeta$ in the type-III model can be broader when the dictated parameter $chi_F$ is positive; however, for negative $chi_F$, the limits are stricter than those in the type-II model. By using the constrained parameters, we find that the deviation from the SM in the $hto Zgamma$ can be of ${cal O}(10%)$. Additionally, we also study the top-quark flavor-changing processes induced at the tree level in the type-III model and find that when all current experimental data are considered, we get $Br(tto c(h, H) )< 10^{-3}$ for $m_h=125.36$ and $m_H=150$ GeV and $Br(tto cA)$ slightly exceeds $10^{-3}$ for $m_A =130$ GeV.
Download