Gaugino mediated supersymmetry breaking

We consider supersymmetric theories where the standard-model quark and lept on fields are localized on a `3-brane' in extra dimensions, while the gauge and Higgs fields propagate in the bulk. If supersymmetry is broken on anot her 3-brane, supersymmetry breaking is communicated to gauge and Higgs fiel ds by direct higher-dimension interactions, and to quark and lepton fields via standard-model loops. We show that this gives rise to a realistic and p redictive model for supersymmetry breaking. The size of the extra dimension s is required to be of order 10-100 times larger than fundamental scale (e. g. the string scale). The spectrum is similar to (but distinguishable from) the predictions of `no-scale' models. Flavor-changing neutral currents are naturally suppressed. The mu term can be generated by the Giudice-Masiero mechanism. The supersymmetric CP problem is naturally solved if CP violatio n occurs only on the observable sector 3-brane. These are the simplest mode ls in the literature that solve all supersymmetric naturalness problems.