Scale dependence of quark mass matrices in models with flavor symmetries.

Numerical correlations between fermion masses and mixings could indicate the presence of a flavor symmetry at high energies. In general, the search for these correlations using low-energy data requires an estimate of leading-log radiative corrections. We present a complete analysis of the evolution between the electroweak and the grand unification scales of quark mass parameters in minimal supersymmetric models. We take Mt = 180 GeV and consider all possible values of tanβ. We also analize the possibility that the top and/or the bottom Yukawa couplings result from an intermediate quasifixed point (QFP) of the equations. We show that the quark mixings of the third family do not have a QFP behaviour (in contrast to the masses, the renormalization of all the mixings is linear), and we evaluate the low-energy value of Vub which corresponds to Vub(MX) = 0. Then we focus on the renormalization-group corrections to (i) typical relations obtained in models with flavor symmetries at the unification scale and (ii) a superstring-motivated pattern of quark mass matrices. We show that in most of the models the numerical prediction for Vub can be corrected in both directions (by varying tanβ) due to top or bottom radiative corrections.