Study of ${\chi }_{cJ}$ radiative decays into a vector meson

The decays ${\chi }_{cJ}\to \gamma V$ ($V=\varphi ,{\rho }^0,\omega$) are studied with a sample of radiative $\text{psip}\to \gamma {\chi }_{cJ}$ events in a sample of $(1.06\pm 0.04)\times {10}^8\text{psip}$ events collected with the BESIII detector. The branching fractions are determined to be: ${\cal B}(\chi_{c1}\to \gamma\phi)=(25.8\pm 5.2\pm 2.3)\times 10^{-6}$,${\cal B}(\chi_{c1}\to \gamma\rho^0)=(228\pm 13\pm 22)\times 10^{-6}$,and${\cal B}(\chi_{c1}\to \gamma\omega)=(69.7\pm 7.2\pm 6.6)\times 10^{-6}$\mathrm{.}Thedecay$\chi_{c1}\to \gamma\phi$ is observed for the first time. Upper limits at the 90% confidence level on the branching fractions for ${\chi }_{c0}$ and $\text{chict}$ decays into these final states are determined. In addition, the fractions of the transverse polarization component of the vector meson in ${\chi }_{c1}\to \gamma V$ decays are measured to be $0.29_{-0.12-0.09}^{+0.13+0.10}$ for $\chi_{c1}\to \gamma\phi$,$0.158\pm 0.034^{+0.015}{-0.014}$for$\chi{c1}\to \gamma\rho^0$,and$0.247_{-0.087-0.026}^{+0.090+0.044}$for$\chi_{c1}\to \gamma\omega$, respectively. The first errors are statistical and the second ones are systematic.