Supergravity-induced E8 gauge hierarchies

We consider the gauge breaking of supergravity-based E8 grand unified gauge group to E6 in the zeroth order of supergravity at Planck mass scale M and E6 to SO(10) at a scale ξ, where ξis a small supergravity expansion parameter of the order of 10/sup -4/. Then surprisingly we find that the subsequent breaking of SO(10) to SU(5), SU(5) to G/sub std/[equivalentSU(2)/sub L/ x U(1)/sub Y/ x SU(3)/sub C/], and G/sub std/ to G/sub L//sub E/[equivalentSU(3)/sub C/ x U(1)/sub Q/] occur at scales ξ2''M, ξ2numberM, and ξ2$M, respectively, with local supersymmetry breaking at the weak scale in the visible sector