Observation of $e^{+}{e}^{-}\to {\hat{I}}^3\ddot{I}{‡}_{c1}$ and search for $e^{+}{e}^{-}\to {\hat{I}}^3\ddot{I}{‡}_{c0},{\hat{I}}^3\ddot{I}{‡}_{c2},$ and ${\hat{I}}^3\hat{I}{\cdot }_c$ at $\sqrt{s}$ near 10.6 GeV at Belle

Abstract

Using data samples of 89.5~fb${}^{-1}$, 711.0~fb${}^{-1}$, and 121.4~fb${}^{-1}$ collected with the Belle detector at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider at center-of-mass energies 10.52 GeV, 10.58 GeV, and 10.867 GeV, respectively, we study the exclusive reactions $e^{+}{e}^{-}\to {\hat{I}}^3\ddot{I}{‡}_{cJ}$ ($J=0,1,2$) and $e^{+}{e}^{-}\to {\hat{I}}^3\hat{I}{\cdot }_c$. A significant ${\hat{I}}^3\ddot{I}{‡}_{c1}$ signal is observed for the first time at $\sqrt{s}=10.58$ GeV with a significance of $5.1\ddot{I}ƒ$ including systematic uncertainties. No significant excesses for ${\hat{I}}^3\ddot{I}{‡}_{c0}$, ${\hat{I}}^3\ddot{I}{‡}_{c2}$, and ${\hat{I}}^3\hat{I}{\cdot }_c$ final states are found, and we set 90\% credibility level upper limits on the Born cross sections ($\ddot{I}{ƒ}_{\mathrm{B}}$) at 10.52 GeV, 10.58 GeV, and 10.867~GeV. Together with cross sections measured by BESIII at lower center-of-mass energies, the energy dependency of $\ddot{I}{ƒ}_{\mathrm{B}}(e^{+}{e}^{-}\to {\hat{I}}^3\ddot{I}{‡}_{c1})$ is obtained.

8 pages, 4 figures