Gauge Fields, Fermions and Mass Gaps in 6D Brane Worlds

TL;DR

This paper analyzes fluctuations in 6D brane world models, deriving exact solutions for Kaluza-Klein spectra, and shows how finite mass gaps and field localization can occur despite large extra dimensions.

Contribution

It provides exact solutions for Kaluza-Klein modes in 6D warped brane models and explores how mass gaps and field localization behave with power-law warping.

Findings

Zero mode wave functions can be peaked on negative tension branes.

Kaluza-Klein mass gap remains finite even in infinite volume limit.

Standard Model fields could feel large extra dimensions while maintaining an effective 4D description.

Abstract

We study fluctuations about axisymmetric warped brane solutions in 6D minimal gauged supergravity. Much of our analysis is general and could be applied to other scenarios. We focus on bulk sectors that could give rise to Standard Model gauge fields and charged matter. We reduce the dynamics to Schroedinger type equations plus physical boundary conditions, and obtain exact solutions for the Kaluza-Klein wave functions and discrete mass spectra. The power-law warping, as opposed to exponential in 5D, means that zero mode wave functions can be peaked on negative tension branes, but only at the price of localizing the whole Kaluza-Klein tower there. However, remarkably, the codimension two defects allow the Kaluza-Klein mass gap to remain finite even in the infinite volume limit. In principle, not only gravity, but Standard Model fields could `feel' the extent of large extra dimensions, and still be described by an effective 4D theory.