Split Supersymmetry Under GUT and Current Dark Matter Constraints
  We recalculate the two-loop beta functions for three gauge couplings taking
into account all low energy threshold corrections in split supersymmetry
(split-SUSY) which assumes a very high scalar mass scale M_S. We find that, in
split-SUSY with gaugino mass unification assumption and a large M_S, the gauge
coupling unification requires a lower bound on gaugino mass. Combined with the
constraints from the dark matter relic density and direct detection limits, we
find that split-SUSY is very restricted and for dark matter mass below 1 TeV
the allowed parameter space can be fully covered by XENON-1T(2017).
