Measurement of Branching Fractions for $B\to η_c K^{(*)}$ Decays

We report measurements of branching fractions for charged and neutral $B\to \eta_c K$ decays where the $\eta_c$ meson is reconstructed in the $K_S^0 K^{\pm}\pi^{\mp}, K^+ K^- \pi^0, K^{*0} K^-\pi^+$ and $p \bar{p}$ decay channels. The neutral $B^0$ channel is a CP eigenstate and can be used to measure the CP violation parameter $\sin 2\phi_1$. We also report the first observation of the $B^0\to \eta_c K^{*0}$ mode. The results are based on an analysis of 29.1 fb$^{-1}$ of data collected by the Belle detector at KEKB.