New determination of |V ub /V cb | from B s 0 → { K −, D s − } μ + ν

Bolognani, Carolina; van Dyk, Danny; Vos, K. Keri

Abstract

We update the full set of B¯s → K form factors using light-cone sum rules with an on-shell kaon. Our approach determines the relevant sum rule parameters — the duality thresholds — from a Bayesian fit for the first time. Using a modified version of the Boyd-Grinstein-Lebed parametrisation, we combine our sum rule results at low momentum transfer q2 with more precise lattice QCD results at large q2. We obtain a consistent description of the form factors in the full q2 range. Applying these results to a recent LHCb measurement of branching ratios for the decays Bs0 → {K−, Ds−}μ+νμ, we determine the ratio of Cabibbo-Kobayashi-Maskawa elementsVubVcbq2<7GeV2=0.0681±0.0040andVubVcbq2>7GeV2=0.0801±0.0047, which are mutually compatible at the 1.9σ level. We further comment on the sensitivity to Beyond the Standard Model effects through measurements of the shape of Bs0 → K−μ+νμ decays, in light of recent limits on such effects from other exclusive b → uℓν processes.

Citation

Bolognani, C., van Dyk, D., & Vos, K. K. (2023). New determination of |V ub /V cb | from B s 0 → { K −, D s − } μ + ν. Journal of High Energy Physics, 2023(11), Article 82. https://doi.org/10.1007/jhep11%282023%29082

• Journal Article Type: Article
• Acceptance Date: Oct 24, 2023
• Online Publication Date: Nov 14, 2023
• Publication Date: 2023-11
• Deposit Date: Nov 20, 2023
• Publicly Available Date: Nov 20, 2023
• Journal: Journal of High Energy Physics
• Print ISSN: 1126-6708
• Electronic ISSN: 1029-8479
• Publisher: Scuola Internazionale Superiore di Studi Avanzati (SISSA)
• Peer Reviewed: Peer Reviewed
• Volume: 2023
• Issue: 11
• Article Number: 82
• DOI: https://doi.org/10.1007/jhep11%282023%29082
• Keywords: Semi-Leptonic Decays, Bottom Quarks, CKM Parameters
• Public URL: https://durham-repository.worktribe.com/output/1932358