Electroweak Penguin Contributions in $B^-(\overline {B_d^0}) \to PP$ and $PV$ decays Beyond Leading Logarithms

Using the next-to-leading order low energy effective Hamiltonian for $|\Delta B|=1$, $\Delta C=\Delta U=0$ transitions, the contributions of electroweak penguin operators in $B^-(\overline {B_d^0})\rightarrow PP$ and $PV$ decays are estimated in the standard model. We find that, for some channels, the electroweak penguin effects can enhance or reduce the QCD penguin and/or tree level contributions by at least $30\%$, and can even play dominant role.