Dual models of gauge unification in various dimensions Original Research Article

We construct a compactification of the heterotic string on an orbifold image leading to the standard model spectrum plus vector-like matter. The standard model gauge group is obtained as an intersection of three image subgroups of image. Three families of image image-plets are localized at three equivalent fixed points. Gauge coupling unification favours existence of an intermediate GUT which can have any dimension between five and ten. Various GUT gauge groups occur. For example, in six dimensions one can have image, image or image, depending on which of the compact dimensions are large. The different higher-dimensional GUTs are ‘dual’ to each other. They represent different points in moduli space, with the same massless spectrum and ultraviolet completion.