The Delta B = - Delta Q transitions and B_d leftrightarrow bar B_d oscillations

We estimate the product of the relative strength of the $\Delta B = -\Delta Q$ amplitude in the decay $B_d^0 \rightarrow D^{*} \ell \bar \nu_{\ell }$ and the width-difference parameter $y$. For this we have used the data on time-dependence of $B_{d}^0\bar B_{d}^0$ oscillations in Z decays and the fraction of like-sign dilepton events at the $\Upsilon (4S)$.