We study two-body $B$-meson decays to a charmonium state ($\eta_c$, $\eta_c(2S)$ or $h_c$) and a $K^+$ or $K^{ *0}(892)$ meson using a sample of $349 fb^{ -1}$ of data collected with the BABAR detector at the PEP-II asymmetric-energy $B$ Factory at SLAC. We measure $BR(B^0\to\eta_c K^{ *0})=(5.7\pm0.6 (stat)\pm0.9 (syst))\times 10^{ -4}$, $BR(B^0\to\eta_c(2S) K^{ *0})<3.9\times 10^{ -4}$, $BR(B^+\to h_c K^+)\times BR(h_c\to\eta_c\gamma)<4.8\times 10^{ -5}$ and $BR(B^0\to h_c K^{ *0})\times BR(h_c\to\eta_c\gamma)<2.2\times 10^{ -4}$ at the 90% C.L., and $BR(\eta_c(2S)\to K \bar{ K} \pi)=(1.9\pm0.4 (stat) \pm1.1 (syst))%$. We also measure the mass and width of the $\eta_c$ meson to be $m(\eta_c)=(2985.8\pm 1.5(stat) \pm 3.1 (syst)) MeV/c^2$ and $\Gamma(\eta_c)=(36.3^{ +3.7}_{ -3.6} (stat) \pm 4.4 (syst)) MeV$.
Categories: hep-ex