Measurement of branching fractions and polarization in B → φK(*) decays

We present the first measurement of decay amplitudes in $B\\ensuremath{\\rightarrow}\\ensuremath{\\varphi}{K}^{*}$ and measurements of branching fractions in $B\\ensuremath{\\rightarrow}\\ensuremath{\\varphi}{K}^{(*)}$ decays based on $78.1\\text{ }{\\mathrm{f}\\mathrm{b}}^{\\ensuremath{-}1}$ of data recorded at the $\\ensuremath{\\Upsilon}(4S)$ resonance with the Belle detector at the KEKB ${e}^{+}{e}^{\\ensuremath{-}}$ storage ring. The decay amplitudes for the different $\\ensuremath{\\varphi}{K}^{*0}$ helicity states are measured from the angular distributions of final state particles in the transversity basis. The longitudinal and transverse complex amplitudes are $|{A}_{0}{|}^{2}=0.43\\ifmmode\\pm\\else\\textpm\\fi{}0.09\\ifmmode\\pm\\else\\textpm\\fi{}0.04$, $|{A}_{\\ensuremath{\\perp}}{|}^{2}=0.41\\ifmmode\\pm\\else\\textpm\\fi{}0.10\\ifmmode\\pm\\else\\textpm\\fi{}0.04$, $\\mathrm{arg}({A}_{\\ensuremath{\\parallel}})=\\ensuremath{-}2.57\\ifmmode\\pm\\else\\textpm\\fi{}0.39\\ifmmode\\pm\\else\\textpm\\fi{}0.09$, and $\\mathrm{arg}({A}_{\\ensuremath{\\perp}})=0.48\\ifmmode\\pm\\else\\textpm\\fi{}0.32\\ifmmode\\pm\\else\\textpm\\fi{}0.06$. The direct $CP$-violating asymmetries are found to be consistent with zero.