Bottom-up and top-down approaches to low energy supersymmetry breaking

In this thesis we address the phenomenology of SUSY breaking from the superstring scale to the electroweak scale in order to produce a guide map for discovery at the LHC. From the top-down approach we study SUSY breaking at low-energies from a well defined superstring theory scenario and extract its phenomenological implications. From the bottom-up approach (independent of string theory), using Bayesian inference techniques, we make the first complete model-independent scan of the low energy phenomenological MSSM (pMSSM) parameter space. We perform the first statistically convergent pMSSM global fit to all current collider and DM data. We demonstrate the application of Bayesian model selection methodology to high energy SUSY breaking models with modest number of free parameters. We found that SUSY breaking from superstring theory should eventually help test its reality and that direct data is required in order to assign unambiguous preferences between different high energy SUSY breaking models. We predict that the Higgs boson mass lies between 117 GeV and 128 GeV at 95% confidence level. We believe this is a robust prediction that should be confirmed once SUSY is discovered at the LHC. Our pMSSM parameters fit provides an appropriate arena for the LHC studies of the MSSM which we wish to pursue further in future work.EThOS - Electronic Theses Online ServiceGBUnited Kingdo