NEW TOOLS FOR LOW-ENERGY DYNAMICAL SUPERSYMMETRY BREAKING

We report the construction of large new classes of models which break supersymmetry dynamically. We then turn to model building. Two of the principal obstacles to constructing simple models of dynamical supersy mmetry breaking are the appearance of Fayet-Iliopoulos D terms and dif ficulties in generating a mu term for the Higgs fields. Among the new models are examples in which symmetries prevent the appearance of Faye t-Iliopoulos terms. A gauge singlet field, which may play a role in ex plaining the hierarchy in quark and lepton parameters, can generate a suitable mu term. The result is a comparatively simple model, with a l ow energy structure similar to that of the MSSM, but with far fewer ar bitrary parameters. We begin the study of the phenomenology of these m odels.