SU(5) Compatible Yukawaon Model With Two Family Symmetries   U(3)$\times$O(3)
  A yukawaon model which is compatible with an SU(5) GUT model is investigated. In a previous SU(5) compatible yukawaon model with a U(3) family gauge symmetry, we could not build a model with a lower energy scale of the family gauge symmetry breaking scale $\Lambda_{fam}$ than $10^{13}$ GeV, so the family gauge boson effects in the previous model were invisible. In the present model, we consider two family symmetries U(3)$\times$O(3), and we assume that the conventional quarks and leptons $(\bar{\bf 5}+{\bf 10}+{\bf 1})$ of SU(5) are described as $(\bar{\bf 5}_i+{\bf 10}_\alpha+{\bf 1}_\alpha)$ ($ i=1,2,3$ and $\alpha=1,2,3$ are indices of U(3) and O(3), respectively). As a result, we build a model with $\Lambda_{O3} \sim 10^{16}$ GeV and $\Lambda_{U3} \sim 10^{3}$ GeV. The lightest U(3) family gauge boson $A_1^1$ will be observed with a mass of the order of 1 TeV. 
Yoshio Koide
hep-ph