Measurement of the Decay Amplitudes and Branching Fractions of $\mathit{B}\to \mathit{J}\mathit{/}\psi K^{*}$ and $\mathit{B}\to \mathit{J}\mathit{/}\psi \mathit{K}$ Decays

Using data taken with the CLEO II detector at the Cornell Electron Storage Ring, we present the first full angular analysis in the color-suppressed modes $B^0\to J/\psi K^{*0\mathrm{}}$ and $B^{+}\to J/\psi K^{*+}$. This leads to a complete determination of the decay amplitudes of these modes including the longitudinal polarization ${\gamma }_L/\gamma =0.52\mathrm{}\pm 0.07\pm 0.04$ and the $P$ wave component $|P{|}^2=0.16\mathrm{}\pm 0.08\pm 0.04$. In addition, we update the branching fractions for $B\to J/\psi K$ and $B\to J/\psi K^{*}$.