\mu \nu$.

Rare $B\rightarrow  K^{*}  \nu  \bar{\nu}  $ Decay
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The main reason for studying the decay $B\rightarrow  K^{*} \nu
\bar{\nu} $ is that in contrast to the decay $B\rightarrow  K^{*}
\ell  \bar{\ell}  $, where $\ell$ is a charged lepton, its differential decay rate does not have any singularity at $q^{2}=0$. In the standard model, $B\rightarrow  K^{*}  \nu
\bar{\nu} $ decay is governed by $Z^{0}$ penguin diagrams and box diagrams. The decay $B\rightarrow K^{*} \ell \bar{\ell} $ has an additional structure $\sigma_{\mu\nu}q_{\nu}/q^{2}$, which dominates the decay rate [@OT91]. This does not occur, of course, in those calculations that stay away from the $q^2=0$ region. Moreover, the decay $B\rightarrow  K^{*} \nu \bar{\nu} $ is a good process theoretically , since both the perturbative $\alpha_{s}$ and nonperturbative $1/m^{2}_{b}$ corrections are known to be small [@GrLiNa].

Contributions from the $Z^{0}$ penguin diagrams and box diagrams are sensitive functions of the top quark mass $m_{t}$. Thus, they contain an uncertainty due to the dependence of $m_{t}$ on the choice of the renormalization scale $\mu $. As stressed in ref. [@BB], in order to reduce this uncertainty, it is necessary to calculate $O(\alpha_{s})$ corrections to these diagrams involving internal top quark exchanges. The resulting effective 