Studying B1(1/2+)→B2(1/2+)ℓ+ℓ- semileptonic weak baryon decays with the SU(3) flavor symmetry.

Motivated by recent anomalies in flavor changing neutral current b→sℓ+ℓ- transitions, we study B1→B2ℓ+ℓ-(ℓ=e,μ,τ) semileptonic weak decays with the SU(3) flavor symmetry, where B1,2 are the spin-12 baryons of single bottomed antitriplet Tb3, single charmed antitriplet Tc3, or light baryons octet T8. Using the SU(3) irreducible representation approach, we first obtain the amplitude relations among different decay modes and then predict the relevant not-yet measured observables of Tb3→T8ℓ+ℓ-, Tc3→T8ℓ+ℓ-, and T8→T′8ℓ+ℓ- decays. (a) We calculate the branching ratios of the Tb3→T8μ+μ- and Tb3→T8τ+τ- decay modes in the whole q² region and in the different q² bins by the measurement of Λ0b→Λ0μ+μ-. Many of them are obtained for the first time. In addition, the longitudinal polarization fractions and the leptonic forward-backward asymmetries of all Tb3→T8ℓ+ℓ- decays are very similar to each other in certain q² bins due to the SU(3) flavor symmetry. (b) We analyze the upper limits of B(Tc3→T8ℓ+ℓ-) by using the experimental upper limits of B(Λ+c→pμ+μ-) and B(Λ+c→pe+e-), and find the experimental upper limit of B(Λ+c→pμ+μ-) giving the effective bounds on the relevant SU(3) flavor symmetry parameters. The predictions of B(Ξ0c→Ξ0e+e-) and B(Ξ0c→Ξ0μ+μ-) will be different between the single-quark transition dominant contributions and the W-exchange dominant ones. (c) As for T8→T′8ℓ+ℓ- decays, we analyze the single-quark transition contributions and the W-exchange contributions by using the two experimental measurements of B(Ξ0→Λ0e+e-) and B(Σ+→pμ+μ-), and give the branching ratio predictions by assuming either single-quark transition dominant contributions or the W-exchange dominant contributions. According to our predictions, some observables are accessible to the experiments at BESIII, LHCb and Belle-II. [ABSTRACT FROM AUTHOR]