Yukawaon Model with U(3)$\times$S$_3$ Family Symmetries
  A new yukawaon model is investigated under a family symmetry U(3)\times S_3. In this model, all vacuum expectation values (VEVs) of the yukawaons, <Y_f>, are described in terms of a fundamental VEV matrix <\Phi_0> as in the previous yukawaon model, but the assignments of quantum number for fields are different from the previous ones: the fundamental yukawaon \Phi_0 is assigned to (3,3) of U(3) \times U(3), which is broken into (3,1+2) of U(3) \times S_3, although quarks and leptons are still assigned to triplets of U(3) and yukawaons Y_f are assigned to 6^* of U(3). Then, VEV relations among Yukawaons become more concise considerably than the previous yukawaon models. By adjusting parameters, we can fit not only quark mixing parameters but also lepton mixing parameters together with their mass ratios. 
Yoshio Koide and Hiroyuki Nishiura
hep-ph