Branching fractions, polarisation and asymmetries of B -> VV decays
Abstract
We calculate the hard-scattering kernels relevant to the negative-helicity decay amplitude in B decays to two vector mesons in the framework of QCD factorisation. We then perform a comprehensive analysis of the 34 B->VV decays, including Bs decays and the complete set of polarisation observables. We find considerable uncertainties from weak annihilation and the non-factorisation of spectator-scattering. Large longitudinal polarisation is expected with certainty only for a few tree-dominated colour-allowed modes, which receive small penguin and spectator-scattering contributions. This allows for an accurate determination of the CKM angle alpha (or gamma) from SL(rhorho) resulting in alpha=(85.6+7.4-7.3) degrees. We also emphasize that the rho K* system is ideal for an investigation of electroweak penguin effects.
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