We found that in supersymmetric models with R-parity non-conservation the b-quarks may appreciably contribute to exotic neutrinoless muon-electron conversion in nuclei via the triangle diagram with two external gluons. This allowed us to extract previously overlooked constraints on the third generation trilinear R-parity violating parameters significantly more stringent than those existing in the literature.
@article{arxiv.hep-ph/0107292,
title = {B-quark mediated neutrinoless $\mu^--e^-$ conversion in presence of R-parity violation},
author = {T. S. Kosmas and Sergey Kovalenko and Ivan Schmidt},
journal= {arXiv preprint arXiv:hep-ph/0107292},
year = {2009}
}