2023/09/22 by Xiao-Gang He, Xiao-Dong Ma, He, Xiao-Gang +3
Physics and Astronomy · #Black Holes and Theoretical Physics #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2309.12741
openalex publication_date 2023/09/22 · openalex created_date 2023/09/26 · openalex updated_date 2026/07/28
Belle II has recently reported the new measurement \cal B(B+→ K+νν)=(2.3±0.7)× 10-5 \citeBelle-II:2023esi which is two times larger than their previous result (although consistent within errors) and about 2.7 σ higher than the SM prediction. We re-examine new physics scenarios we have discussed previously which can enhance this rate to determine if they can accommodate the higher value reported in the new measurement. We use consistency with existing bounds on B→ K^*νν, b→ s ℓ+ℓ-, B→ D(*)ℓν and Bs mixing to limit possible explanations for the excess. For the case of LFV neutrino couplings, we find that only two leptoquarks remain viable requiring a large C9^′ττ=-C10^′ττ. For models with different types of light dark matter particle pairs (scalar, fermion, or vector), the preliminary q2 distribution from Belle II, which shows that the excess appears mostly for bins with 3≤ q2≤7 GeV2 \citeBelle-II:2023esi, implies only the vector current operators with scalar or vector dark matter particles with masses in the hundreds of MeV can match the anomaly.