@MISC{Randall99alarge, author = {Lisa Randall}, title = {A large mass hierarchy from a small extra dimension}, year = {1999} }

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Abstract

We propose a new higher-dimensional mechanism for solving the hierarchy problem. The weak scale is generated from a large scale of order the Planck scale through an exponential hierarchy. However, this exponential arises not from gauge interactions but from the background metric (which is a slice of AdS5 spacetime). This mechanism relies on the existence of only a single additional dimension. We demonstrate a simple explicit example of this mechanism with two three-branes, one of which contains the Standard Model fields. The experimental consequences of this scenario are new and dramatic. There are fundamental spin-2 excitations with mass of weak scale order, which are coupled with weak scale as opposed to gravitational strength to the standard model particles. The phenomenology of these models is quite distinct from that of large extra dimension scenarios; none of the current If spacetime is fundamentally higher dimensional with 4+n spacetime dimensions, then the effective four-dimensional (reduced) Planck scale, MPl = 2 ×10 18 GeV, is determined by the fundamental (4+n)-dimensional Planck scale, M, and the geometry of the extra dimensions.