Observation of $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{bJ}$ and search for $X_b\to \ddot{I}‰\hat{I}\yen (1S)$ at $\sqrt{s}\sim 10.867$ GeV

Abstract

The $e^{+}{e}^{-}\to \ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{bJ}$ ($J=0,1,2$) processes are studied using a 118~fb${}^{-1}$ data sample collected at a center-of-mass energy of 10.867 GeV, in the $\hat{I}\yen (10860)$ energy range, with the Belle detector. The $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{b1}$, $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{b2}$, $\ddot{I}‰\ddot{I}{‡}_{b1}$ signals and the evidence of $\ddot{I}‰\ddot{I}{‡}_{b2}$ are observed for the first time and the cross sections are measured. No significant $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0\ddot{I}{‡}_{b0}$ or $\ddot{I}‰\ddot{I}{‡}_{b0}$ signal is observed and 90\% confidence level upper limits on the cross sections for these two processes are obtained. In the $\ddot{I}{€}^{+}\ddot{I}{€}^{-}\ddot{I}{€}^0$ invariant mass spectrum, significant non-$\ddot{I}‰$ signals are also observed. We search for the $X(3872)$-like state with a hidden $b\bar{b}$ component (named $X_b$) decaying into $\ddot{I}‰\hat{I}\yen (1S)$; no significant signal is observed with a mass between $10.55$ and $10.65$ GeV/$c^2$.

7 pages, 3 figures, accepted for publication as a Letter in Physical Review Letters