B→Kπ decays with 1/mb corrections in QCD factorization

A careful investigation of 1/mb power-suppressed effects is crucial for enhancing predictive power of the QCD factorization approach to charmless B decays. It is instructive to systematically investigate the 1/mb effects from soft- and hard-gluon exchanges, in addition to annihilation topology in the charmless B decays. In this work we try to give a systematic discussion on impact of such soft and hard exchanges on the penguin-dominated B→Kπ decays within the framework of the light-cone QCD sum rules (LCSR). For the weak phase γ(=ImVub*) ranging from 40 deg. to 80 deg. , we find that because of the annihilation and soft and hard exchanges a numerical increase of 20-30% is expected in the branching ratios up to O(1/mb2) corrections; the resultant soft and hard corrections are less important than the annihilation contributions and amount only to a level of 10%. Possible sources of uncertainties are discussed in some details