@Article{BelleIICollaborationAbudinen+Marinas2021, author="Belle II Collaboration (Abudinen, F. et al and Marinas, C.", title="Search for B+ -> K+nu(nu)over-bar Decays Using an Inclusive Tagging Method at Belle H", journal="Physical Review Letters", year="2021", publisher="Amer Physical Soc", volume="127", number="18", pages="181802 - 10pp", abstract="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.", optnote="WOS:000712526000010", optnote="exported from refbase (https://references.ific.uv.es/refbase/show.php?record=5020), last updated on Tue, 25 Jan 2022 08:04:15 +0000", issn="0031-9007", doi="10.1103/PhysRevLett.127.181802", opturl="https://arxiv.org/abs/2104.12624", opturl="https://doi.org/10.1103/PhysRevLett.127.181802", language="English" }