Fat penguins and imaginary penguins in perturbative QCD

We evaluate $B\to K\pi$ decay amplitudes in perturbative QCD picture. This result is compared with results of factorization approximation. We shall show that pQCD gives dynamical enhancement of penguin operators by nearly 50%. It is also shown that anihilation diagrams are not negligible. In fact they give large contribution and that they give large final state interaction phase. We also present our results for branching ratios for $B\to K\pi$ for representative parameter set.