Towards a realistic grand gauge-Higgs unification

We investigate a 5D SU(6) grand gauge-Higgs unification model compactified on an orbifold S-1/Z(2). Ordinary quarks and leptons, together with right-handed neutrinos, are just accommodated into a minimal set of representations of the gauge group, without introducing any exotic states in the same representations. The proton decay turns out to be forbidden at least at the tree level. We also find a correct electroweak symmetry breaking SU(2)(L) x U(1)(Y) -> U(1)(em) is easily realized by introducing suitable number of adjoint fermions. (C) 2007 Elsevier B.V. All rights reserved.