Model with gauge coupling unification on an S1/(Z2 x Z2′) orbifold

We propose a simple grand unified theory in which the fifth dimensional coordinate is compactified on an S-1/(Z(2) x Z(2)(')) orbifold. We propose two models within this theory, one containing an additional 10 + (10) over bar and one containing an additional 15 + (15) over bar, together with two 24 Higgs multiplets in the non-supersymmetric SU(5) grand unified theory. Although this theory is a non-supersymmetric theory, gauge coupling unification is realized through the mass splittings of Higgs multiplets by S-1/(Z(2) X Z(2)(')) orbifolding. The constraints from b --> sgamma and mu --> egamma and from electron and muon anomalous magnetic moments are also discussed.