RevisitingB→ πK,πK* and ρKdecays: CP violations and implication for new physics

Abstract

Combining the up-to-date experimental information on B → πK,πK* and ρK decays, we revisit the decay rates and CP asymmetries of these decays within the framework of QCD factorization. Using an infrared finite gluon propagator of Cornwall prescription, we find that the time-like annihilation amplitude could contribute a large strong phase, while the space-like hard spectator scattering amplitude is real. Numerically, we find that all the branching ratios and most of the direct CP violations, except ACP(B± → K±π0), agree with the current experimental data with an effective gluon mass mg 0.5 GeV. Taking the unmatched difference in direct CP violations between B → π0K± and πK± decays as a hint of new physics, we perform a model-independent analysis of new physics contributions with a set of (1+γ5)b⊗(1+γ5)q (q=u,d) operators. Detail analyses of the relative impacts of the operators are presented in five cases. Fitting the twelve decay modes, parameter spaces are found generally with nontrivial weak phases. Our results may indicate that both strong phase from annihilation amplitude and new weak phase from new physics are needed to resolve the πK puzzle. To further test the new physics hypothesis, the mixing-induced CP violations in B → π0KS and ρ0KS are discussed and good agreements with the recent experimental data are found.