Old Ideas for New Physicists 2

We review ideas relating the breaking of Supersymmetry in de Sitter (dS) space-time to amplitudes in which gravitinos are reflected from the dS horizon. A self consistent evaluation of such amplitudes leads to the estimate $m_{3/2} = K \Lambda^{1/4}$, with a constant $K$ that is not easily calculable. LHC bounds on superpartner masses, plus the structure of low energy effective field theory then imply that there must be new superfields with standard model quantum numbers in the region below $100$ TeV. Only one class of models, the Pyramid Schemes, has been found, which is compatible with one loop coupling unification. They have a new strongly coupled gauge sector with a confinement scale in the multi TeV region. We outline the general predictions of these models, which include Dirac gauginos and a novel solution of the strong CP problem. The models all appear to have a "little hierarchy problem": the expectation value of the standard model Higgs field, and its mass, must be a factor of $10$ or more smaller than the masses of the second Higgs doublet or standard model superpartners. Since all of these models contain uncertainties from the strong coupling physics, as well as the physics of the dS horizon, it is difficult to determine how serious this fine tuning problem is.