Measurement of branching fractions for B \to J/ψηK decays and search for a narrow resonance in the J/ψηfinal state

Belle Collaboration, T. Iwashita, K. Miyabayashi +178

We report an observation of the $B^{\pm }\to J/\psi \eta K^{\pm }$ and $B^0\to J/\psi \eta K_S^0$ decays using 772$\times 10^6$ $B\bar{B}$ pairs collected at the ${\rm Y}(4S)$ resonance with the Belle…