Search for new hadronic decays of ${h}_{c}$ and observation of ${h}_{c}\to {K}^{+}{K}^{-}{\pi }^{+}{\pi }^{-}{\pi }^{0}$

Ten hadronic final states of the ${h}_{c}$ decays are investigated via the process $\psi \left(3686\right)\to {\pi }^{0}{h}_{c}$, using a data sample of $\left(448.1±2.9\right)×{10}^{6}\text{}\text{}\psi \left(3686\right)$ events collected with the BESIII detector. The decay channel ${h}_{c}\to {K}^{+}{K}^{-}{\pi }^{+}{\pi }^{-}{\pi }^{0}$ is observed for the first time and has a measured significance of $6.0\sigma $. The corresponding branching fraction is determined to be $B\left({h}_{c}\to {K}^{+}{K}^{-}{\pi }^{+}{\pi }^{-}{\pi }^{0}\right)=\left(3.3±0.6±0.6\right)×{10}^{-3}$ (where the uncertainties are statistical and systematic, respectively). Evidence for the decays ${h}_{c}\to {\pi }^{+}{\pi }^{-}{\pi }^{0}\eta $ and ${h}_{c}\to {K}_{S}^{0}{K}^{±}{\pi }^{\mp }{\pi }^{+}{\pi }^{-}$ is found with a significance of $3.6\sigma $ and $3.8\sigma $, respectively. The corresponding branching fractions (and upper limits) are obtained to be $B\left({h}_{c}\to {\pi }^{+}{\pi }^{-}{\pi }^{0}\eta \right)=\left(7.2±1.8±1.3\right)×{10}^{-3}$ $\left(<1.8×{10}^{-2}\right)$ and $B\left({h}_{c}\to {K}_{S}^{0}{K}^{±}{\pi }^{\mp }{\pi }^{+}{\pi }^{-}\right)=\left(2.8±0.9±0.5\right)×{10}^{-3}$ ($<4.7×{10}^{-3}$). Upper limits on the branching fractions for the final states ${h}_{c}\to {K}^{+}{K}^{-}{\pi }^{0}$, ${K}^{+}{K}^{-}\eta $, ${K}^{+}{K}^{-}{\pi }^{+}{\pi }^{-}\eta $, $2\left({K}^{+}{K}^{-}\right){\pi }^{0}$, ${K}^{+}{K}^{-}{\pi }^{0}\eta $, ${K}_{S}^{0}{K}^{±}{\pi }^{\mp }$, and $p\overline{p}{\pi }^{0}{\pi }^{0}$ are determined at a confidence level of 90%.