Neutrino mass induced radiatively by supersymmetric leptoquarks

We show how nonzero Majorana neutrino masses can be radiatively generated by extending the MSSM with leptoquark chiral multiplets without violating R-parity. It is found that, with these particles, the R-parity conservation does not imply lepton number conservation. Neutrino masses generated at a one-loop level are closely related to the down quark mass matrix. The ratio of neutrino mass-squared splittings $\Delta m^2_{\nu_2-\nu_1}/\Delta m^2_{\nu_3-\nu_2}$ obtained is naturally close to $\Delta m^2_{s-d}/\Delta m^2_{b-s}\sim 10^{-3}$ which is in the right region required to explain both the atmospheric neutrino data and the MSW solutions for the solar neutrino data.