Power corrections in positron-electron decaying to M1M2 and in charmless two body B decays.

摘要

We study the role of power corrections in B meson decays to light meson pairs in order to explain the large deviations from the leading power predictions. To confirm that our results are reasonable, we study the role of similar power corrections in electron-positron annihilation to light meson pairs. The power corrections in electron-positron annihilation can be easily isolated and directly determined from the measured cross-sections. The power corrections in both B decays and electron-positron annihilation are separated into perturbative and non-perturbative (soft) parts. The perturbative parts are obtained by imposing cutoffs on IR logarithmic divergences, and the soft parts are obtained from fits to the data. We find that the data in both B decays and electron-positron annihilation can be accounted for if the soft-to-perturbative power correction ratios are O (10), O (a few), and O (1) for PP, VP, and VV final states, respectively. This agreement increases our confidence that power corrections make O (1) contributions to the QCD penguin amplitudes, and can account for the observed 'puzzles' in B decays. The large soft power corrections for PP final states highlight the special nature of the pseudo-Nambu-Goldstone bosons. The time-dependent asymmetries Sf and Cf for f = Kspi 0 and f = Ks&phis; are well determined by the fits. These results agree with the data, however the measured errors are larger than the errors in the fit suggesting that these observables are a good place to look for New Physics.