Nonuniversal gaugino masses, the supersymmetric little hierarchy problem, and dark matter

We study a class of supersymmetric models with nonuniversal gaugino masses that could arise from F-terms in a general combination of the singlet and adjoint representations of SU(5). We explore models that satisfy present Large Hadron Collider and other bounds, showing how the allowed parameter space is divided into distinct "continents." Regions of parameter space that ameliorate the supersymmetric little hierarchy problem with a small mu parameter include the usual focus-point scenario, but also natural areas with much lighter squarks and sleptons. These models are continuously connected in parameter space to regions in which stau coannihilation or Higgs exchange is mostly responsible for dark matter annihilation, and to models in which the thermal relic abundance is achieved by slepton-mediated annihilation, reviving the bulk region that is severely restricted in minimal supergravity models. In hybrid or confluence regions, several mechanisms combine to give the requisite dark matter annihilation rate. In each case, we study the prospects for direct detection of dark matter. We also comment briefly on the impact of recent hints for M sub(h)near 125 GeV from the LHC.