Tachyonic Squarks in Split Supersymmetry
  The decoupling of scalar particles in split supersymmetry makes the spectrum of squarks irrelevant for low energy processes. Nevertheless, the structure of the vacuum is sensitive to the spectrum of squarks, even when the supersymmetry breaking scale is large. In this note, we show that in certain regions of the parameter space, squarks could develop radiatively tachyonic masses, thus breaking electric charge and color. We discuss the constraints that follow from the requirement of charge and color conservation, and we comment on the implications for model building. 
Alejandro Ibarra