Large Mass Hierarchy from a Small Extra Dimension

TLDR

The authors propose a new higher‑dimensional mechanism to solve the hierarchy problem. They generate the weak scale from the Planck scale via an exponential hierarchy produced by the background metric of a slice of AdS₅, illustrated with a simple two‑brane model where one brane hosts the Standard Model. The resulting models exhibit novel, dramatic phenomenology and evade all current constraints on theories with very large extra dimensions.

Abstract

We propose a new higher-dimensional mechanism for solving the hierarchy problem. The weak scale is generated from 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 ${\mathrm{AdS}}_{5}$ spacetime). We demonstrate a simple explicit example of this mechanism with two 3-branes, one of which contains the standard model fields. The phenomenology of these models is new and dramatic. None of the current constraints on theories with very large extra dimensions apply.