In the 1990s, physics beyond the Standard Model was dominated by a single framework: supersymmetry at the weak scale with an energy desert up to the unification or Planck scales. Over the last two years this picture has been challenged by theories with large extra dimensions, where the arena for new physics is the volume of the extra dimensions rather than the energy of the desert.
Supersymmetry and large extra dimensions will be critically compared from the viewpoint of gauge coupling unification, proton stability, neutrino masses, generation structure and the quark and lepton masses. Extra dimensions allow new ideas for electroweak symmetry breaking, both with and without supersymmetry. Collider and gravity tests will be discussed.
This talk is based on a Plenary Talk on Physics Beyond the Standard Model given at ICHEP2000, Osaka.