Mixing matrix in a model with a singlet quark

On the assumption of the see-saw mechanism of quark-mass generation and with inclusion of the experimental bounds, a generalized mixing matrix is constructed which determines the structure of charged and neutral currents in models with a singlet open-quotes downclose quotes quark. On the basis of this matrix the mass splitting in systems of neutral mesons, branching ratios of rare decays, and decay characteristics of new heavy mesons are calculated. 21 refs., 3 tabs