Observation of $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{b1,2}(1P)$ and search for $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{b1,2}(1P)$ at $\sqrt{s}=$10.96---11.05 GeV

Abstract

We report searches for the processes $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{bJ}$ and $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{bJ}$ (J=1,2) based on data samples collected by the Belle experiment at the KEKB collider. We report the first observation of the process $e^{+}{e}^{-}\to (\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0{)}_{\mathrm{non}-\ddot{\mathrm{I}}‰}\ddot{I}{‡}_{b1}$ and first evidence for $e^{+}{e}^{-}\to \ddot{I}‰\ddot{I}{‡}_{bJ}$ in the vicinity of the $\hat{I}\yen (11020)$ resonance, with center-of-mass energies from 10.96 to 11.05~GeV. The significances for $(\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0{)}_{\mathrm{non}-\ddot{\mathrm{I}}‰}\ddot{I}{‡}_{b1}$ and $\ddot{I}‰\ddot{I}{‡}_{bJ}$ are greater than $5.3\ddot{I}ƒ$ and $4.0\ddot{I}ƒ$, respectively. We also investigate the energy dependence of the $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{bJ}$ cross section, but we cannot determine whether the contributions are from the $\hat{I}\yen (10860)$ and $\hat{I}\yen (11020)$ resonances or non-resonant continuum processes. The signals for $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{bJ}$ are not significant, and the upper limits of the Born cross sections at the 90\% confidence level are $0.7$ and $1.0$~pb for $e^{+}{e}^{-}\to \ddot{I}•\ddot{I}{‡}_{b1}$ and $\ddot{I}•\ddot{I}{‡}_{b2}$, respectively, for center-of-mass energies from 10.96 to 11.05~GeV.

8pages, 3 figures