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Branching fractions, polarisation and asymmetries of B -> VV decays

Martin Beneke·Johannes Rohrer·Deshan Yang
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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 B_s 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 S_L(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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Martin Beneke, Johannes Rohrer, Deshan Yang. 2007-05-30. Branching fractions, polarisation and asymmetries of B -> VV decays. https://doi.org/10.1016/j.nuclphysb.2007.03.020

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