Observation of ${\chi }_{c1}$ decays into vector meson pairs $\varphi \varphi$, $\omega \omega$, and $\omega \varphi$

Decays of ${\chi }_{c1}$ to vector meson pairs $\varphi \varphi$, $\omega \omega$ and $\omega \varphi$ are observed for the first time using $(106\pm 4)\times {10}^6$ $\text{psip}$ events accumulated at the BESIII detector at the BEPCII $e^{+}{e}^{-}$ collider. The branching fractions are measured to be $(4.4\pm 0.3\pm 0.5)\times 10^{-4}$,$(6.0\pm 0.3\pm 0.7)\times 10^{-4}$,and$(2.2\pm 0.6\pm 0.2)\times 10^{-5}$,for$\chi_{c1}\to \phi\phi$,$\omega\omega$,and$\omega\phi$, respectively. The observation of ${\chi }_{c1}$ decays into a pair of vector mesons $\varphi \varphi$, $\omega \omega$ and $\omega \varphi$ indicates that the hadron helicity selection rule is significantly violated in ${\chi }_{cJ}$ decays. In addition, the measurement of ${\chi }_{cJ}\to \omega \varphi$ gives the rate of doubly OZI-suppressed decay. Branching fractions for ${\chi }_{c0}$ and ${\chi }_{c2}$ decays into other vector meson pairs are also measured with improved precision.