QUARK MASS MATRICES WITH FULL 1ST-ORDER PERTURBATION

In view of current experimental constraints on the top-quark mass m, and the Cabibbo-Kobayashi-Maskawa (CKM) matrix elements V(ij), we study a modified form of the Fritzsch quark mass matrices, in which two nonzero diagonal elements for the charm and strange quarks are introduced as the additional first-order perturbative terms. In a reasonable analytical approximation, this modification can yield the upper bound of m, twice as much as that predicted by the Fritzsch Ansatz. The magnitudes of the CKM matrix elements and the parametrization-invariant measure of CP violation are restricted very well in terms of ratios of quark masses, and some interesting relations such as \V(ub)/V(cb)\2 almost-equal-to m(u)/m(c), \V(td)/V(ts)\2 almost-equal-to m(d)/m(s), and \V(ub)\ almost-equal-to \V(ts)\ are obtained to better accuracy.