First observation of the decay ${\chi }_{cJ}\to {\Sigma }^{+}\overline{p}{K}_{S}^{0}+c.c.\left(J=0,1,2\right)$

Using E1 radiative transitions $\psi \left(3686\right)\to \gamma {\chi }_{cJ}$ from a sample of $\left(448.1±2.9\right)×{10}^{6}\text{}\text{}\psi \left(3686\right)$ events collected with the BESIII detector, the decays ${\chi }_{cJ}\to {\Sigma }^{+}\overline{p}{K}_{S}^{0}+c.c.\left(J=0,1,2\right)$ are studied. The decay branching fractions are measured to be $B\left({\chi }_{c0}\to {\Sigma }^{+}\overline{p}{K}_{S}^{0}+c.c.\right)=\left(3.52±0.19±0.21\right)×{10}^{-4}$, $B\left({\chi }_{c1}\to {\Sigma }^{+}\overline{p}{K}_{S}^{0}+c.c.\right)=\left(1.53±0.10±0.08\right)×{10}^{-4}$, and $B\left({\chi }_{c2}\to {\Sigma }^{+}\overline{p}{K}_{S}^{0}+c.c.\right)=\left(8.25±0.83±\phantom{\rule{0ex}{0ex}}0.49\right)×{10}^{-5}$, where the first and second uncertainties are the statistical and systematic ones, respectively. No evident intermediate resonances are observed in the studied processes.