Flavor-Changing Neutral Currents Induced by the Democratic Seesaw Mass Matrix

Abstract

Flavor-changing neutral currents (FCNC) are studied on the basis of a ``democratic seesa'' mass matrix model, which yields a singular enhancement of the top-quark mass m_t and can give reasonable quark masses and CKM matrix elements. The most exciting aspect of the model is that the structure of the $6\times 6$ right-handed fermion mixing matrix in the up-quark sector, $U_u^R$, shows an abnormal structure in contrast to that of $U_u^L$. This causes characteristic effects on the right-handed FCNC concerned with top quark. A single top-quark production at future $e^{+}{e}^{-}$ colliders, $e^{+}+e^{-}\to Z_R\to t+\overline{c}$ ($\overline{t}+c$), is discussed.

Comments: 15 pages, Latex, no figure