Polarization in B->VV Decays

Abstract

Factorizable amplitudes in B decays to light vector meson pairs give a longitudinal polarization satisfying 1- f_L =O(1/m_b^2). This remains formally true when non-factorizable graphs are included in QCD factorization, and is numerically realized in B->Rho Rho. In ΔS=1 decays a QCD penguin annihilation graph can effectively contribute at leading power to the transverse and longitudinal amplitudes. The observed longitudinal polarization, f_L (B->phi K^*) \approx 50%, can therefore be accounted for in the SM. The ratio of perpendicular to parallel transverse rates provides a sensitive test for new right-handed currents. The transverse b->sg dipole operator amplitudes are highly suppressed. CP violation measurements can therefore discriminate between new contributions to the dipole and four quark operators. SU(3)_F violation in QCD penguin amplitudes can easily be O}(1), in general, due to annihilation. Implications for B->Rho K^* polarization and New Physics searches are pointed out.