Impacts of the Soft-Gluon Exchanges on B →ππ Decays

We have investigated the role of soft-gluon exchanges in B →ππ, using the light-cone sum rules in quantum chromodynamics. The calculations are carried out not only for the tree operators but also for the penguin operators. We conclude that soft-gluon exchanges contribute to the decay amplitudes, noticeably on some decay channels, and thus cannot be neglected.