We calculate the amplitudes involved in the heavy baryon nonleptonic decay Λb → ΛJ/ψ using perturbative QCD factorization theorem, which are expressed as convolutions of hard b quark decay amplitudes with the Λb baryon, Λ baryon and J/ψ meson distribution amplitudes. It is found that nonfactorizable contributions dominate over factorizable ones. Employing the distribution amplitudes determined in our previous works, we derive the branching ratio B(Λb → ΛJ/ψ) = (1.65 ∼ 5.27) × 10-4 in agreement with data. We predict an asymmetry parameter α = -0.17 ∼ -0.14 associated with the anisotropic angular distribution of the Λ baryons produced in polarized Λb baryon decays.
All Science Journal Classification (ASJC) codes
- Atomic and Molecular Physics, and Optics
- Nuclear and High Energy Physics
- Astronomy and Astrophysics