Three-family GUT models from heterotic orbifold on E6 root lattice

We construct three-family supersymmetric GUT models from heterotic string. We investigate compactifications on non-factorizable torus defined by E6 root lattice, which admits automorphism of Z3 × Z3. Interestingly some of the twisted sectors from the Z3 × Z3 orbifold on E6 root lattice have just three fixed tori respectively, and generate three degenerate massless states. We assume only non-standard gauge embeddings and find that it leads to SU(5) and SO(10) GUT models. These models also include strongly coupled sectors in the low energy and messenger states charged with both hidden and visible sectors. ∗E-mail address: [email protected]