2015/03/24 by Y. Liu, Liu, Y., L. -L. Liu +3
Physics and Astronomy · #FOS: Physical sciences #High Energy Physics - Phenomenology (hep-ph) #High-Energy Particle Collisions Research #Particle physics theoretical and experimental studies #Quantum Chromodynamics and Particle Interactions
paper · pdf · doi:10.48550/arxiv.1503.06907
openalex publication_date 2015/03/24 · openalex created_date 2024/04/11 · openalex updated_date 2026/07/28
In our previous work, based on the SU(6) spin-flavor wave function, we regard Λ and p as composed of different quark-diquark configurations and established the Bethe-Salpeter (BS) equations of configurations for quark and scalar diquark. In our present work, we apply this model to calculate the form factors of the semileptonic transitions Λb→Λl+l- (l=μ,e,τ) and Λb→ p lν within the Standard Model (SM). The decay Λb→Λμ+μ- is especially interesting since it has been measured in CDF and LHCb Collaborations and this rare decay is very sensitive to new physics effects. The decay Λb→ p lν is a promising mode for the measurement of the Cabibbo-Kobayashi-Maskawa matrix element |Vub| at the Large Hadron Collider. In our calculations, depending on the ranges of the parameters in the model including the diquark mass and the interaction strength between the quark and the diquark in the kernel of the BS equation, we find that the branching ratio of Λb→Λμ+μ- in our model is consistent with the experimental data and the current experimental results from LHCb agree with the differential branching ratio of Λb→Λμ+μ- from our calculation except at the lager momentum transfer region. This indicates that there is still room for possible new physics effects. We also give comparisions of the total branching ratios of Λb→Λl+l- and Λb→ p lν with those given by other phenomenological methods.