%0 Journal Article
%T Search for B+ -> K+nu(nu)over-bar Decays Using an Inclusive Tagging Method at Belle H
%A Belle II Collaboration (Abudinen, F. et al
%A Marinas, C.
%J Physical Review Letters
%D 2021
%V 127
%N 18
%I Amer Physical Soc
%@ 0031-9007
%G English
%F BelleIICollaborationAbudinen+Marinas2021
%O WOS:000712526000010
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5020), last updated on Tue, 25 Jan 2022 08:04:15 +0000
%X A search for the flavor-changing neutral-current decay B+ -> K+nu(nu) over bar is performed at the Belle II experiment at the SuperKEKB asymmetric energy electron-positron collider. The data sample corresponds to an integrated luminosity of 63 fb(-1) collected at the Upsilon(4S) resonance and a sample of 9 fb(-1) collected at an energy 60 MeV below the resonance. Because the measurable decay signature involves only a single charged kaon, a novel measurement approach is used that exploits not only the properties of the B+ -> K+nu(nu) over bar decay, but also the inclusive properties of the other B meson in the Upsilon(4S) -> B (B) over bar event, to suppress the background from other B 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+ -> K+nu(nu) over bar of 4.1 x 10(-5) is set at the 90% confidence level.
%R 10.1103/PhysRevLett.127.181802
%U https://arxiv.org/abs/2104.12624
%U https://doi.org/10.1103/PhysRevLett.127.181802
%P 181802 - 10pp