Study of the decays ${\chi }_{cJ}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}\omega$

Using $(27.12\pm 0.14)\times {10}^8$ $\psi (3686)$ events collected with the BESIII detector, we present the first observation of the decays ${\chi }_{cJ}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}\omega$, where $J=0,1,2$, with statistical significances of $11.7\sigma ,11.2\sigma$, and $11.8\sigma$. The branching fractions of these decays are determined to be $\mathcal{B}({\chi }_{c0}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}\omega )=(2.37\pm 0.22\pm 0.23)\times {10}^{-4}$, $\mathcal{B}({\chi }_{c1}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}\omega )=(1.01\pm 0.10\pm 0.11)\times {10}^{-4}$, and $\mathcal{B}({\chi }_{c2}\to \mathrm{\Lambda }\bar{\mathrm{\Lambda }}\omega )=(1.40\pm 0.13\pm 0.17)\times {10}^{-4}$, where the first uncertainties are statistical and the second are systematic. We observe no clear intermediate structures.