Implications of the quark mass hierarchy on flavour mixings

We stress that the observed pattern of flavour mixings can be partly interpreted by the quark mass hierarchy without the assumption of specific quark mass matrices. The quantitatively proper relations between the Kobayashi-Maskawa matrix elements and quark mass ratios, such as vertical bar Vcb vertical bar approx.= vertical bar V15 vertical bar approx.= √2 ((ms)/mb - (mc)/mt) [1+3 ((ms)/mb + (mc)/mt)] are obtainable from a simple ansatz of flavour permutation symmetry breaking at the weak scale. We prescribe the same ansatz at the scale of supersymmetric grand unified theories, and find that its all low-energy consequences on flavour mixings and CP violation are in good agreement with current experimental data. (author)