We analyse the two purely isospin-violating decays Λb→Σ0ϕ and Λb→Σ0J/ψ, proceed merely via the exchange topologies, in the framework of perturbative QCD approach. Assuming Σ0 baryon belongs to the idealized isospin triplet with quark components of usd, the branching ratios of the two decay modes are predicted to be tiny, of the order 10−8−10−9, leading to a difficulty in observing them. We then extend our study to include the Σ−Λ mixing.It is found that the mixing has significant effect on the Λb→Σ decays, especially it can greatly increase the rate of the J/ψ process, by as much as two orders of magnitude, yield 10−7, which should be searchable in the future. We also estimate a set of asymmetry observables with and without the mixing effect, which will be tested in coming experiments.
@article{arxiv.2308.02262,
title = {Estimates of the isospin-violating $\Lambda_b\rightarrow \Sigma^0 \phi, \Sigma^0 J/\psi$ decays and the $\Sigma-\Lambda$ mixing},
author = {Zhou Rui and Jia-Ming Li and Chao-Qi Zhang},
journal= {arXiv preprint arXiv:2308.02262},
year = {2023}
}