Evidence for $B^{+}\to h_c{K}^{+}$ and observation of ${\eta }_c(2S)\to p\bar{p}{\pi }^{+}{\pi }^{-}$

A search for the decays $B^{+}\to h_c{K}^{+}$ and $B^0 \rightarrow h_c K_S^0$isperformed\mathrm{.}Evidenceforthedecay$B^+ \rightarrow h_c K^+$ is found; its significance is $4.8\sigma$. No evidence is found for $B^0 \rightarrow h_c K_S^0$\mathrm{.}Thebranchingfractionfor$B^+ \rightarrow h_c K^+$ismeasuredtobe$(3.7^{+1.0}{-0.9}{}^{+0.8}{-0.8}) \times 10^{-5}$;theupperlimitforthe$B^0 \rightarrow h_c K_S^0$branchingfractionis$1.4 \times 10^{-5}$at$90%$C\mathrm{.}L\mathrm{.}Inaddition,astudyofthe$p \bar{p} \pi^+ \pi^-$ invariant mass distribution in the channel $B^{+}\to (p\bar{p}{\pi }^{+}{\pi }^{-})K^{+}$ results in the first observation of the decay ${\eta }_c(2S)\to p\bar{p}{\pi }^{+}{\pi }^{-}$ with $12.1\sigma$ significance. The analysis is based on the 711 ${\mathrm{f}\mathrm{b}}^{-1}$ data sample collected by the Belle detector at the asymmetric-energy $e^{+}{e}^{-}$ collider KEKB at the $\mathrm{{\rm Y}}(4S)$ resonance.