Solving the Hierarchy Problem with Noncompact Extra Dimensions

TL;DR

This paper proposes a model where global cosmic 3-branes in six dimensions lead to natural compactification, explaining the hierarchy between electroweak and gravitational forces through gravitational effects and boundary conditions.

Contribution

It introduces a novel mechanism where cosmic 3-branes cause compactification and hierarchy generation via gravitational effects in noncompact extra dimensions.

Findings

Finite transverse dimensions with exponentially large radius

Space-time boundary conditions resolve naked singularity issues

Hierarchy between forces explained by geometric effects

Abstract

We show that gravitational effects of global cosmic 3-branes can be responsible for compactification from six to four space-time dimensions, naturally producing the observed hierarchy between electroweak and gravitational forces. The finite radius of the transverse dimensions follows from Einstein's equation, and is exponentially large compared with the scales associated with the 3-brane. The space-time ends on a mild naked singularity at the boundary of the transverse dimensions; nevertheless unitary boundary conditions render the singularity harmless.