Implications of new evidence for lepton-universality violation in b →sℓ+ℓ- decays

Geng, Li-Sheng, Grinstein, Benjamín, Jager, Sebastian, Li, Shuang-Yi, Camalich, Jorge Martin and Shi, Rui-Xiang (2021) Implications of new evidence for lepton-universality violation in b →sℓ+ℓ- decays. Physical Review D, 104 (3). a035029 1-9. ISSN 2470-0010

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Motivated by renewed evidence for new physics in b→sℓℓ transitions in the form of LHCb's new measurements of theoretically clean lepton-universality ratios and the purely leptonic Bs→μ+μ- decay, we quantify the combined level of discrepancy with the Standard Model and fit values of short-distance Wilson coefficients. A combination of the clean observables RK, RK∗, and Bs→μμ alone results in a discrepancy with the Standard Model at 4.0σ, up from 3.5σ in 2017. One-parameter scenarios with purely left-handed or with purely axial coupling to muons fit the data well and result in a ∼5σ pull from the Standard Model. In a two-parameter fit of new-physics contributions with both vector and axial-vector couplings to muons the allowed region is much more restricted than in 2017, principally due to the much more precise result on Bs→μ+μ-, which probes the axial coupling to muons. Including angular observables data restricts the allowed region further. A by-product of our analysis is an updated average of BR(Bs→μ+μ-)=(2.8±0.3)×10-9.

Item Type: Article
Schools and Departments: School of Mathematical and Physical Sciences > Physics and Astronomy
SWORD Depositor: Mx Elements Account
Depositing User: Mx Elements Account
Date Deposited: 25 Apr 2022 07:49
Last Modified: 25 Apr 2022 08:00

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