  Two loop renormalization group equations for dimensionless as well as
dimensionful parameters are obtained for the low energy theories that result
from decoupling heavy scalar particles in Split SUSY and Effective SUSY
scenarios, assuming that only a single Higgs field survives at low energy. For
the Effective SUSY case two scenarios are considered: first, when the only
light third generation scalars are the partners of the left-handed quark
doublet and the right-handed top quark --which yields the minimal matter
content compatible with naturalness-- and second, when all the scalars of the
third generation are light. These beta functions implementing decoupling will
be useful to avoid the problems of perturbation theory in the MSSM in a
mass-independent scheme such as DR-bar when large hierarchies in the spectrum
are present.
