Zb/Zb′→Υπandhbπdecays in intermediate meson loops model

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With the recent measurement of ${Z}_{b}(10610)$ and ${Z}_{b}(10650)\ensuremath{\rightarrow}B{\overline{B}}^{*}+\mathrm{c}.\mathrm{c}.$ and ${B}^{*}{\overline{B}}^{*}$, we investigate the transitions from the ${Z}_{b}(10610)$ and ${Z}_{b}(10650)$ to bottomonium states with emission of a pion via intermediate $B{B}^{*}$ meson loops. The experimental data can be reproduced in this approach with a commonly accepted range of values for the form factor cutoff parameter $\ensuremath{\alpha}$. The $\ensuremath{\Upsilon}(3S)\ensuremath{\pi}$ decay channels appear to experience obvious threshold effects which can be understood by the property of the loop integrals. By investigating the $\ensuremath{\alpha}$-dependence of partial decay widths and ratios between different decay channels, we show that the intermediate $B{B}^{*}$ meson loops are crucial for driving the transitions of ${Z}_{b}/{Z}_{b}^{\ensuremath{'}}\ensuremath{\rightarrow}\ensuremath{\Upsilon}(nS)\ensuremath{\pi}$ with $n=1$, 2, 3, and ${h}_{b}(mP)\ensuremath{\pi}$ with $m=1$ and 2.