Flipped SU(5) from Z12−I orbifold with Wilson line

We construct a three family flipped SU(5) model from the heterotic string theory compactified on the Z12−I orbifold with one Wilson line. The gauge group is SU(5)×U(1)X×U(1)3×[SU(2)×SO(10)×U(1)2]′. This model does not derive any non-Abelian group except SU(5) from E8, which is possible only for two cases in case of one shift V, one in Z12−I and the other in Z12−II. We present all possible Yukawa couplings. We place the third quark family in the twisted sectors and two light quark families in the untwisted sector. From the Yukawa couplings, the model provides the R-parity, the doublet-triplet splitting, and one pair of Higgs doublets. It is also shown that quark and lepton mixings are possible. So far we have not encountered a serious phenomenological problem. There exist vector-like flavor SU(5) exotics (including Qem=±16 color exotics and Qem=±12 electromagnetic exotics) and SU(5) vector-like singlet exotics with Qem=±12 which can be removed near the GUT scale. In this model, sin2θW0=38 at the full unification scale.