Branching fraction measurements ofB→ηcKdecays

We study the decays $B^{+}\to {\eta }_c{K}^{+}$ and $B^0\to {\eta }_c{K}^0,$ where the ${\eta }_c$ is reconstructed in the $K_S^0{K}^{\pm }{\pi }^{\mp }$ and $K^{+}{K}^{-}{\pi }^0$ decay modes. Results are based on a sample of 86 million $B\overline{B}$ pairs collected with the BABAR detector at the SLAC $e^{+}{e}^{-}$ B Factory. We measure the product of branching fractions $\mathcal{B}{(B}^{+}\to {\eta }_c{K}^{+})\times \mathcal{B}({\eta }_c\to K\overline{K}\pi )=(7.40\mathrm{}\pm 0.50\pm 0.70)\times {10}^{-5}$ and $\mathcal{B}{(B}^0\to {\eta }_c{K}^0)\times \mathcal{B}({\eta }_c\to K\overline{K}\pi )=(6.48\mathrm{}\pm 0.85\pm 0.71)\times {10}^{-5},$ where the first error is statistical and the second is systematic. In addition, we search for $\overrightarrow{B}{\eta }_{c}K$ events with ${\eta }_c\to {2(K}^{+}{K}^{-})$ and ${\eta }_c\to \phi \phi$ and determine the ${\eta }_c$ decay branching fraction ratios $\mathcal{B}({\eta }_c\to {2(K}^{+}{K}^{-}))/\mathcal{B}({\eta }_c\to K\overline{K}\pi )=(2.3\mathrm{}\pm 0.7\pm 0.6)\times {10}^{-2}$ and