Observation of $e^{+}{e}^{-}\to K\bar{K}J/\psi$ at center-of-mass energies from 4.189 to 4.600 GeV

Abstract

We investigate the process $e^{+}{e}^{-}\to K\bar{K}J/\psi$ at center-of-mass energies from 4.189 to 4.600 GeV using 4.7 fb${}^{-1}$ of data collected by the BESIII detector at the BEPCII collider. The Born cross sections for the reactions $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$ and $K_S^0{K}_S^{0}J/\psi$ are measured as a function of center-of-mass energy. The energy dependence of the cross section for $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$ is shown to differ from that for ${\pi }^{+}{\pi }^{-}J/\psi$ in the region around the $Y(4260)$. In addition, there is evidence for a structure around 4.5 GeV in the $e^{+}{e}^{-}\to K^{+}{K}^{-}J/\psi$ cross section that is not present in ${\pi }^{+}{\pi }^{-}J/\psi$.

8 pages, 3 figures