What can we learn from B→ρ(ω)K decays?

We show that in the PQCD approach the B→ρ(ω)K decays display not only the dynamical penguin enhancement, the mechanism responsible for the large branching ratios (BRs) of B→φK decays, but also the importance of annihilation contributions. We find that the CP asymmetries (CPAs) of B→ρ±K∓, B∓→ρ0(ω)K∓ (class I) are all over 50%.