The Hierarchy Problem, Extra Dimensions and Gravitational Resonances at Colliders
The motivations and basic properties of extra dimensions will be reviewed. A new scenario involving one extra dimension will be presented which can explain the immense hierarchy between the strength of the weak interactions (Fermi's Constant) and that of gravity (Newton's Constant). The hierarchy is naturally large because it has an exponential dependence on the size of the extra dimension. A robust prediction of this model is the appearance of TeV-mass spin-2 resonances in upcoming colliders. Although these resonances are excitations of the ordinary graviton they are observable because they couple to matter with roughly Standard Model strength. There will be more pictures than equations.