Study of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>η</mml:mi></mml:math> and dipion transitions in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">ϒ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>4</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> decays to lower bottomonia
Study of <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mi>η</mml:mi></mml:math> and dipion transitions in <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:mrow><mml:mi mathvariant="normal">ϒ</mml:mi><mml:mo stretchy="false">(</mml:mo><mml:mn>4</mml:mn><mml:mi>S</mml:mi><mml:mo stretchy="false">)</mml:mo></mml:mrow></mml:math> decays to lower bottomonia
We study hadronic transitions between bottomonium states using $496\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ data collected at the $\mathrm{\ensuremath{\Upsilon}}(4S)$ resonance with the Belle detector at the KEKB asymmetric energy ${e}^{+}{e}^{\ensuremath{-}}$ collider. We measure $\mathcal{B}(\mathrm{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{\ensuremath{\Upsilon}}(1S))=(8.2\ifmmode\pm\else\textpm\fi{}0.5(\text{stat})\ifmmode\pm\else\textpm\fi{}0.4(\text{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, $\mathcal{B}(\mathrm{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{\ensuremath{\Upsilon}}(2S))=(7.9\ifmmode\pm\else\textpm\fi{}1.0(\text{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.4(\text{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}5}$, and $\mathcal{B}(\mathrm{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}\ensuremath{\eta}\mathrm{\ensuremath{\Upsilon}}(1S))=(1.70\ifmmode\pm\else\textpm\fi{}0.23(\text{stat})\ifmmode\pm\else\textpm\fi{}0.08(\text{syst}))\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}4}$. We measure the ratio of branching fractions $\mathcal{R}=\mathcal{B}(\mathrm{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}\ensuremath{\eta}\mathrm{\ensuremath{\Upsilon}}(1S))/\mathcal{B}(\mathrm{\ensuremath{\Upsilon}}(4S)\ensuremath{\rightarrow}{\ensuremath{\pi}}^{+}{\ensuremath{\pi}}^{\ensuremath{-}}\mathrm{\ensuremath{\Upsilon}}(1S))=2.07\ifmmode\pm\else\textpm\fi{}0.30(\text{stat})\ifmmode\pm\else\textpm\fi{}\phantom{\rule{0ex}{0ex}}0.11(\text{syst})$. We search for the decay $\mathrm{\ensuremath{\Upsilon}}(1{^{3}D}_{1,2})\ensuremath{\rightarrow}\ensuremath{\eta}\mathrm{\ensuremath{\Upsilon}}(1S)$, but do …