Dynamical supersymmetry breaking at low energies

Conventional approaches to supersymmetric model building suffer from several naturalness problems: they do not explain the large hierarchy between the weak scale and the Planck mass, and they require fine-tuning to avoid large flavor-changing neutral currents and particle electric dipole moments. The existence of models with dynamical supersymmetry breaking, which can explain the hierarchy, has been known for some time, but efforts to build such models have suffered from unwanted axions and difficulties with asymptotic freedom. In this paper we describe an approach to model building with supersymmetry broken at comparatively low energies which solves these problems, and give a realistic example.