Measurement of Branching Fractions and Polarization in B -> phi K^((*)) Decays

We present the first measurement of decay amplitudes in B -> phi K^* and measurements of branching fractions in B -> phi K^{(*)} decays based on 78.1 fb^{-1} of data recorded at the Upsilon(4S) resonance with the Belle detector at the KEKB e^+ e^- storage ring. The decay amplitudes for the different phi K^{*0} helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitudes are |A_0|^2 = 0.43 +- 0.09 +- 0.04, |A_perp|^2 = 0.41 +- 0.10 +- 0.04, arg(A_parallel) = -2.57 +- 0.39 +- 0.09, and arg(A_perp) = 0.48 +- 0.32 +- 0.06. The direct CP-violating asymmetries are found to be consistent with zero.