GUTs on orbifold

We consider 5 dimensional E6, E7, and E8 supersymmetric grand unified theories (GUTs) on an orbifold S/Z2, in which the Higgs fields arise from the 5th components of the 5D gauge fields. We introduce matter fields in 5 dimensions, then the Yukawa interactions are induced from the gauge interactions among the 5th component of gauge fields and the bulk hyper-multiplets. The adjoint and fundamental representations of bulk matter fields can induce all Yukawa interactions of the standard model in E6 GUT. Furthermore, realistic fermion mass hierarchies and flavor mixings with the CP violating phase can be reproduced by introducing the 4D brane localized fields and their interactions. E7 and E8 GUTs can produce all Yukawa interactions by introducing only adjoint matter hyper-multiplet in the bulk. The charge quantization and anomaly free structure on the 4D wall are satisfactory in our models.