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Search for $B^{+}to K^{+} ubar{ u}$ decays using an inclusive tagging method at Belle II

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 نشر من قبل Simon Kurz
 تاريخ النشر 2021
  مجال البحث
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A search for the flavor-changing neutral-current decay $B^{+}to K^{+} ubar{ u}$ is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The results are based on a data sample corresponding to an integrated luminosity of $63,mbox{fb}^{-1}$ collected at the $Upsilon{(4S)}$ resonance and a sample of $9,mbox{fb}^{-1}$ collected at an energy $60mathrm{,Mekern -0.1em V}$ below the resonance. A novel measurement method is employed, which exploits topological properties of the $B^{+}to K^{+} ubar{ u}$ decay that differ from both generic bottom-meson decays and light-quark pair production. This inclusive tagging approach offers a higher signal efficiency compared to previous searches. No significant signal is observed. An upper limit on the branching fraction of $B^{+}to K^{+} ubar{ u}$ of $4.1 times 10^{-5}$ is set at the 90% confidence level.

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