A search for the decays $B^{+}\to h_c{K}^{+}$ and $B^0\to h_c{K}_S^0$ is performed. Evidence for the decay $B^{+}\to h_c{K}^{+}$ is found; its significance is $4.8\sigma$. No evidence is found for $B^0\to h_c{K}_S^0$. The branching fraction for $B^{+}\to h_c{K}^{+}$ is measured to be $({3.7}_{-0.9}^{+1.0}{}_{-0.8}^{+0.8})\times {10}^{-5}$; the upper limit for the $B^0\to h_c{K}_S^0$ branching fraction is $1.4\times {10}^{-5}$ at 90% C.L. In addition, a study of the $p\overline{p}{\pi }^{+}{\pi }^{-}$ invariant mass distribution in the channel $B^{+}\to (p\overline{p}{\pi }^{+}{\pi }^{-})K^{+}$ results in the first observation of the decay ${\eta }_c(2S)\to p\overline{p}{\pi }^{+}{\pi }^{-}$ with $12.1\sigma$ significance. The analysis is based on the $711{\mathrm{fb}}^{-1}$ data sample collected by the Belle detector at the asymmetric-energy $e^{+}{e}^{-}$ collider KEKB at the $\mathrm{\Upsilon }(4S)$ resonance.

• Received 15 March 2019

DOI:https://doi.org/10.1103/PhysRevD.100.012001

Published by the American Physical Society under the terms of the Creative Commons Attribution 4.0 International license. Further distribution of this work must maintain attribution to the author(s) and the published article’s title, journal citation, and DOI. Funded by SCOAP³.

Published by the American Physical Society