Abstract
The nonlinear
σ
-model for disordered interacting electrons is studied in spatial dimensions
d>4
. The critical behavior at the metal-insulator transition is determined exactly, and found to be that of a standard Landau-Ginzburg-Wilson
ϕ
4
-theory with the single-particle density of states as the order parameter. All static exponents have their mean-field values, and the dynamical exponent
z=3
.
∂n/∂μ
is critical with an exponent of
1/2
, and the electrical conductivity vanishes with an exponent
s=1
. The transition is qualitatively different from the one found in the same model in a
2+ϵ
expansion.