2021/05/12 by F. Dattola, Dattola, Filippo
Engineering · Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #Particle Accelerators and Free-Electron Lasers #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2105.05754
openalex publication_date 2021/05/12 · openalex created_date 2022/07/25 · openalex updated_date 2026/07/28
This contribution illustrates a new search for the flavor-changing neutral-current decay B+ → K+ ν ν performed by the Belle II experiment at the SuperKEKB asymmetric-energy electron-positron collider. In this study, a sample corresponding to an integrated luminosity of 63 \rmfb-1 collected at the \rm Υ(4S) resonance and an additional sample of 9 \rmfb-1 collected at an energy 60 \rm MeV below the resonance are used. A novel technique, based on an inclusive tagging method and exploiting the topological features of the B+ → K+ ν ν decay, is employed and it provides a higher signal efficiency with respect to the methods used in the previous searches. No significant signal is observed. An upper limit of 4.1 × 10-5 is set on the B+ → K+ ν ν branching fraction at the 90 % confidence level.