Search for transitions from $\mathrm{\Upsilon }(4S)$ and $\mathrm{\Upsilon }(5S)$ to ${\eta }_b(1S)$ and ${\eta }_b(2S)$ with emission of an $\omega$ meson

Using data collected in the Belle experiment at the KEKB asymmetric-energy $e^{+}{e}^{-}$ collider we search for transitions $\mathrm{\Upsilon }(4S)\to {\eta }_b(1S)\omega$, $\mathrm{\Upsilon }(5S)\to {\eta }_b(1S)\omega$ and $\mathrm{\Upsilon }(5S)\to {\eta }_b(2S)\omega$. No significant signals are observed and we set 90% confidence level upper limits on the corresponding visible cross sections: 0.2 pb, 0.4 pb and 1.9 pb, respectively.

Figure 1

The $M({\pi }^{+}{\pi }^{-}{\pi }^0)$ distribution for the $\mathrm{\Upsilon }(4S)\to {\eta }_b(1S)\omega$ candidates. Red lines indicate the $\omega$ mass requirement.

Figure 2

The $M_{\text{recoil}}({\pi }^{+}{\pi }^{-}{\pi }^0)$ distribution for the $\mathrm{\Upsilon }(4S)\to {\eta }_b(1S)\omega$ candidates. Top: data points with the fit function overlaid; note the suppressed zero on the vertical scale. Bottom: residuals between the data and the fit function. The solid line shows the fit function for the best fit; the dashed line shows the same function with the yield fixed to the upper limit.

Figure 3

The $M_{\text{recoil}}({\pi }^{+}{\pi }^{-}{\pi }^0)$ distribution for the $\mathrm{\Upsilon }(5S)\to {\eta }_b(1S)\omega$ candidates; note the suppressed zero on the vertical scale. Symbols are the same as those in Fig. 2.

Figure 4

The $M_{\text{recoil}}({\pi }^{+}{\pi }^{-}{\pi }^0)$ distribution for the $\mathrm{\Upsilon }(5S)\to {\eta }_b(2S)\omega$ candidates; note the suppressed zero on the vertical scale. Symbols are the same as those in Fig. 2.

Figure 5

The $M_{\text{recoil}}({\pi }^{+}{\pi }^{-}{\pi }^0)$ distribution for the $\mathrm{\Upsilon }(5S)\to {\chi }_{bJ}(1P)\omega$ candidates; note the suppressed zero on the vertical scale. Symbols are the same as those in Fig. 2.