  We re-examine mode-coupling theory for the Kardar-Parisi-Zhang (KPZ) equation
in the strong coupling limit and show that there exists two branches of
solutions. One branch (or universality class) only exists for dimensionalities
$d<d_c=2$ and is similar to that found by a variety of analytic approaches,
including replica symmetry breaking and Flory-Imry-Ma arguments. The second
branch exists up to $d_c=4$ and gives values for the dynamical exponent $z$
similar to those of numerical studies for $d\ge2$.
