Abstract
In analysing five dimensional orbifolds with exceptional gauge groups, we seek to find stable vacua configurations which satisfy the minimal requirements for asymptotic grand unified models. In this respect we show that no minimal asymptotic grand unified theory can be built. Our results point towards non-minimal models based on
E
6
: one featuring supersymmetry, and the other needing a modification of the Coleman–Weinberg potential to stabilise the breaking of
E
6
to the standard model gauge group.