The rare decay b→ssdˉ is studied in a vector quark model by adding the contributions from exotic vector-like quarks. We find that the contribution from box diagrams amounts to 10−9 in the branching ratio, while the Z-mediated tree level contribution is negligible.
Cite
@article{arxiv.hep-ph/0410144,
title = {b \to ss\bar{d}$ in a Vector Quark Model},
author = {Hai-Ying Cai and Da-Xin Zhang},
journal= {arXiv preprint arXiv:hep-ph/0410144},
year = {2014}
}