jats:titleAjats:scbstract</jats:sc> </jats:title>jats:pUsing a dataset corresponding to 9 fbjats:supjats:italic−</jats:italic>1</jats:sup> of integrated luminosity collected with the LHCb detector between 2011 and 2018 in proton-proton collisions, the decay-time distributions of the decay modes jats:inline-formulajats:alternativesjats:tex-math$$ {B}_s^0\to J/{\psi \eta}^{\prime } $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:msubsup mml:miB</mml:mi> mml:mis</mml:mi> mml:mn0</mml:mn> </mml:msubsup> mml:mo→</mml:mo> mml:miJ</mml:mi> mml:mo/</mml:mo> mml:msup mml:miψη</mml:mi> mml:mo′</mml:mo> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula> and jats:inline-formulajats:alternativesjats:tex-math$$ {B}_s^0\to J/\psi {\pi}^{+}{\pi}^{-} $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:msubsup mml:miB</mml:mi> mml:mis</mml:mi> mml:mn0</mml:mn> </mml:msubsup> mml:mo→</mml:mo> mml:miJ</mml:mi> mml:mo/</mml:mo> mml:miψ</mml:mi> mml:msup mml:miπ</mml:mi> mml:mo+</mml:mo> </mml:msup> mml:msup mml:miπ</mml:mi> mml:mo−</mml:mo> </mml:msup> </mml:math></jats:alternatives></jats:inline-formula> are studied. The decay-width difference between the light and heavy mass eigenstates of the jats:inline-formulajats:alternativesjats:tex-math$$ {B}_s^0 $$</jats:tex-math><mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML"> mml:msubsup mml:miB</mml:mi> mml:mis</mml:mi> mml:mn0</mml:mn> </mml:msubsup> </mml:math></jats:alternatives></jats:inline-formula> meson is measured to be ∆Γjats:subjats:italics</jats:italic></jats:sub> = 0jats:italic.</jats:italic>087 ± 0jats:italic.</jats:italic>012 ± 0jats:italic.</jats:italic>009 psjats:supjats:italic−</jats:italic>1</jats:sup>, where the first uncertainty is statistical and the second systematic.</jats:p>