Observation of a structure in ${e}^{+}{e}^{-}\to \varphi {\eta }^{\prime }$ at $\sqrt{s}$ from 2.05 to 3.08 GeV

The process ${e}^{+}{e}^{-}\to \varphi {\eta }^{\prime }$ has been studied for the first time in detail using data sample collected with the BESIII detector at the BEPCII collider at center of mass energies from 2.05 to 3.08 GeV. A resonance with quantum numbers ${J}^{PC}={1}^{--}$ is observed with mass $M=\left(2177.5±4.8\left(\mathrm{stat}\right)±19.5\left(\mathrm{syst}\right)\right)\mathrm{MeV}/{c}^{2}$ and width $\Gamma =\left(149.0±15.6\left(\mathrm{stat}\right)±8.9\left(\mathrm{syst}\right)\right)\text{}\text{}\mathrm{MeV}$ with a statistical significance larger than $10\sigma $, including systematic uncertainties. If the observed structure is identified with the $\varphi \left(2170\right)$, then the ratio of partial width between the $\varphi {\eta }^{\prime }$ by BESIII and $\varphi \eta $ by BABAR is (${B}_{\varphi \eta }^{R}{\Gamma }_{ee}^{R}\right)/\left({B}_{\varphi {\eta }^{\prime }}^{R}{\Gamma }_{ee}^{R}\right)=\phantom{\rule{0ex}{0ex}}0.23±0.10\left(\mathrm{stat}\right)±0.18\left(\mathrm{syst}\right)$, which is smaller than the prediction of the $s\overline{s}g$ hybrid models by several orders of magnitude.