Search for <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" display="inline"><mml:msubsup><mml:mi>B</mml:mi><mml:mi>s</mml:mi><mml:mn>0</mml:mn></mml:msubsup><mml:mo stretchy="false">→</mml:mo><mml:msup><mml:mi>η</mml:mi><mml:mo>′</mml:mo></mml:msup><mml:msub><mml:mi>X</mml:mi><mml:mrow><mml:mi>s</mml:mi><mml:mover accent="true"><mml:mi>s</mml:mi><mml:mo stretchy="false">¯</mml:mo></mml:mover></mml:mrow></mml:msub></mml:math> at Belle using a semi-inclusive method

We report the first search for the penguin-dominated process ${B}_{s}^{0}\ensuremath{\rightarrow}{\ensuremath{\eta}}^{\ensuremath{'}}{X}_{s\overline{s}}$ using a semi-inclusive method. A $121.4\text{ }\text{ }{\mathrm{fb}}^{\ensuremath{-}1}$ integrated luminosity $\mathrm{\ensuremath{\Upsilon}}(5S)$ data set collected by the Belle experiment, at the KEKB asymmetric-energy ${e}^{+}{e}^{\ensuremath{-}}$ collider, is used. We observe no statistically significant signal and, including all uncertainties, we set a 90% confidence level upper limit on the partial branching fraction at $1.4\ifmmode\times\else\texttimes\fi{}{10}^{\ensuremath{-}3}$ for $M({X}_{s\overline{s}})\ensuremath{\le}2.4\text{ }\text{ }\mathrm{GeV}/{c}^{2}$.