Observation of $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{c1}$ and $\ddot{I}•\ddot{I}{‡}_{c2}$ at $\sqrt{s}$=4.600 GeV

Abstract

Using a data sample collected with the BESIII detector operating at the BEPCII storage ring at a center-of-mass energy of $\sqrt{s}=4.600$ GeV, we search for the production of $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{c0,1,2}$ and the charmonium-like state $Y(4140)$ in the radiative transition $e^{+}{e}^{-}\to {\hat{I}}^{3}Y(4140)$ with $Y(4140)$ subsequently decaying into $\ddot{I}•J/\ddot{I}ˆ$. The processes $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{c1}$ and $\ddot{I}•\ddot{I}{‡}_{c2}$ are observed for the first time, each with a statistical significance of more than 10σ, and the Born cross sections are measured to be $(4.2_{-1.0}^{+1.7}\pm 0.3)$ pb and $(6.7_{-1.7}^{+3.4}\pm 0.5)$ pb, respectively, where the first uncertainties are statistical and the second systematic. No significant signals are observed for $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{c0}$ and $e^{+}{e}^{-}\to {\hat{I}}^{3}Y(4140)$ and upper limits on the Born cross sections at $90\%$ confidence level are provided at $\sqrt{s}=4.600$ GeV.