Quark mixings and mass hierarchy from radiative corrections

We discuss a scheme where both quark mass hierarchy and mixing angles arise out of radiative corrections and are therefore calculable. No horizontal symmetry or Yukawa coupling hierarchy is required. Masses obey the pattern mu:mc:mt ≅ λ2:λ:1 (similarly for the down sector), where λ is the loop expansion parameter. The observed quark isodoublet splitting is also obtained. For the mixing angles, we find an interesting result where Vub is of O(λ2), whereas Vus and Vcb are each of O(λ). We present a model implementing this scheme where a crucial role is played by a pair of isosinglet heavy quarks. (orig.)