Observation of $e^{+}{e}^{-}\to {\pi }^{+}{\pi }^{-}{\pi }^0{\chi }_{bJ}$ and search for $X_b\to \omega {\rm Y}(1S)$ at $\sqrt{s}\sim 10.867$ GeV

Abstract

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

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