Implications of SUSY model building

We discuss the motivations and implications of models of low-energy supersymmetry. We present the case for the minimal supersymmetric standard model, which we define to include the minimal particle content and soft supersymmetry-breaking interactions which are universal at the GUT or Planck scale. This model is in agreement with all present experimental results, and yet depends on only a few unknown parameters and therefore maintains considerable predictive power. From the theoretical side, it arises naturally in the context of supergravity models. We discuss radiative electroweak symmetry breaking and the superpartner spectrum in this scenario, with some added emphasis on regions of parameter space leading to unusual or interesting experimental signals at future colliders. We then examine how these results may be affected by various modifications and extensions of the minimal model, including GUT effects, extended gauge, Higgs, and matter sectors, non-universal supersymmetry breaking, non-conservation of R-parity, and dynamical supersymmetry breaking at low energies.