Contribution of $Z_b$ resonances to ${\rm Y}(5S)\to \pi \pi \pi {\chi }_b$

Abstract

We discuss the recently presented Belle results on the decays ${\rm Y}(5S)\to \pi \pi \pi {\chi }_{bJ}(1P)$. The data indicate that in addition to the $\omega$ emission, ${\rm Y}(5S)\to \omega {\chi }_{bJ}$, there is a significant non resonant background in the three pion spectrum. We suggest that a sizable fraction of this background may be associated with the cascade process ${\rm Y}(5S)\to \pi Z_b\to \pi \rho {\chi }_b$ involving the $Z_b(10610)$ and $Z_b(10650)$ resonances. If confirmed by the data, this would be the first observation of transition from the $Z_b$ resonances to lower bottomonium with emission of a light meson state different from a single pion, which may provide a new input in understanding of the internal dynamics of these resonances.

7 pages, 1 figure

Cited by in corpus (5)

• 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
• Bottomonium-like states: physics case for energy scan above the $B\bar{B}$ threshold at Belle-II
• Two charmoniumlike charged axial resonances near 3885 MeV
• Exotic hadrons associated with $b$-quark
• Improved measurement of Born cross sections for ${\chi }_{bJ}\omega$ and ${\chi }_{bJ}({\pi }^{+}{\pi }^{-}{\pi }^0{)}_{\mathrm{non}-\omega }$ ($J$ = 0, 1, 2) at Belle and Belle II