2022/12/06 by Chao-Qiang Geng, Chia-Wei Liu, Geng, Chao-Qiang +3
Physics and Astronomy · #Cosmology and Gravitation Theories #FOS: Physical sciences #High Energy Physics - Experiment (hep-ex) #High Energy Physics - Phenomenology (hep-ph) #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.2212.02976
openalex publication_date 2022/12/06 · openalex created_date 2022/12/20 · openalex updated_date 2026/07/28
We study the decays of Λb → Λ(→ p π-) ℓ + ℓ- with ℓ = (e, μ, τ). In particular, we examine the full angular distributions with polarized Λb and identify the time-reversal asymmetries or T-odd observables. By using the homogeneous bag model, we find that the decay branching fractions of Λb → Λℓ+ℓ- are (9.1± 2.5,7.9± 1.8, 2.1± 0.2)× 10-7 for ℓ =(e, μ,τ), respectively. In addition, we obtain that AFBℓ = -0.369± 0.007 and AFBh=-0.333± 0.004, averaged in the range of 15 ≤ q2 ≤ 20~ GeV2. These results are well consistent with the current experimental data. We also explore the T-odd observables in Λb → Λ(→ p π-) μ+ μ-, which are sensitive to new physics~(NP). Explicitly, we illustrate that the current experimental measurement from one of the T-odd observables favors the existence of NP, such as the extra Z-boson model.