  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 $\Upsilon (4S)$.
