Search for B+ -> K+nu(nu)over-bar Decays Using an Inclusive Tagging Method at Belle H

Abudinen, F.; Adachi, I.; Adamczyk, K.; Ahlburg, P.; Aihara, H.; Akopov, N. und Aloisio, A. (2021): Search for B+ -> K+nu(nu)over-bar Decays Using an Inclusive Tagging Method at Belle H. In: Physical Review Letters, Vol. 127, No. 18, 181802

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.

• Item Type: Journal article
• Faculties: Physics
• Subjects: 500 Science > 530 Physics
• ISSN: 0031-9007
• Language: English