constraint. This is for avoiding excessive exclusion of a possibility that a combined contribution of the other dimension six operators, which we do not discuss directly here, compensates the positive effect of $\Delta\rho_{Dt}^{}$. Under the rho parameter constraint, the effect of $C_{Dt}^{}$ becomes much smaller than that of $C_{t1}$.

The width of the Higgs boson $\Gamma_H^{}$ is evaluated by calculating the decay rates for $H\to f\bar f$ ($f$: quarks and charged leptons), $WW^{(\ast)}$, $ZZ^{(\ast)}$, $\gamma\gamma$, $Z\gamma$ and $gg$. At the leading order, they are given from the SM result by replacing the top Yukawa coupling by $y^{\rm eff}_t(m_H^2,\Lambda)$, where the effective coupling $y^{\rm eff}_t(-q^2,\Lambda)$ is defined by $$\begin{aligned}
y^{\rm eff}_t(-q^2,\Lambda) =
 y_t^{\rm SM}
 - v^2 \frac{C_{t1}}{\Lambda^2} 
- q^2 \frac{C_{Dt}}{2 \Lambda^2}, \label{eq:yeff}\end{aligned}$$ where $y_t^{\rm SM}$ ($= \sqrt{2} m_t/v$) is the top Yukawa coupling of the SM, and the rest is the additional contributions of the dimension-six operators. In Fig. \[fig:plot-width\], the values of the total width of the Higgs boson are plotted for each set of $C_{t1}^{}$ and $C_{Dt}^{}$: $(C_{t1}^{}, C_{Dt}^{})=(0,0)$ \[Set A\], $(+16\pi \Lambda/(3\sqrt{2}v),0)$ \[Set B\], $(-16\pi
  \Lambda/(3\sqrt{2}v),0)$ \[Set C\], $(0,+10.2)$ \[Set D\] and $(0,-6.2)$ \[Set E\], according to the unitarity bounds in Eqs. (\[eq:pu-t1\]) and (\[eq:pu-Dt\]). Set A corresponds 