Neutrino masses and mixings in a universal seesaw mass matrix model

Neutrino masses and mixings are investigated on the basis of a universal seesaw mass matrix model, in which quark (except for the top quark) and charged lepton mass matrices $M_f$ and the neutrino mass matrix $M_{\nu }$ are given by $M_f\simeq m_L{M}_F^{-1}{m}_R$ and $M_{\nu }\simeq m_L{M}_F^{-1}{m}_L^T$ $\mathrm{}(F=N)\mathrm{}$, respectively. For a simple model which can successfully describe quark masses and mixings, we find that the observed neutrino data (except for the solar neutrino data) are favorable to the intermediate mass scales ${O(m}_R{)=10\mathrm{}}^{11}$ GeV and ${O(M}_F{)=10\mathrm{}}^{13}$ GeV together with ${O(m}_L{)=10\mathrm{}}^2$ GeV. In spite of the largeness of ${O(m}_R)$, the observed top-quark mass can be consistently understood from the would-be seesaw mass matrix with these mass scales.