Annihilation in charmless nonleptonic B decays

We show that the leading contributions to annihilation amplitudes in nonleptonic B→M1M2 decays (where M1,2 are charmless non-isosinglet mesons) of order αs(mb)Λ/mb are real and are determined by distribution functions that already occur in the lowest order factorization theorem [C.M. Arnesen, Z. Ligeti, I.Z. Rothstein and I.W. Stewart, hep-ph/0607001]. A complex nonperturbative parameter from annihilation first appears at and real at lowest order. Thus, incalculable strong phases are suppressed in annihilation amplitudes, unless the expansion breaks down. Modeling the distribution functions, we find that (11±9)% and (15±11)% of the absolute values of the measured and B−→K−K0 penguin amplitudes come from annihilation. This is consistent with the expected size of power corrections. LBNL–61096