Bulk Fields in the Randall-Sundrum Compactification Scenario

TL;DR

This paper explores how bulk fields in the Randall-Sundrum model can have exponentially suppressed four-dimensional masses, suggesting Standard Model fields might not need to be confined to a 3-brane.

Contribution

It demonstrates that five-dimensional bulk fields with Planck-scale masses can produce low-mass modes, expanding the potential localization of Standard Model fields in the Randall-Sundrum scenario.

Findings

Bulk fields with M_Pl-scale masses yield exponentially suppressed 4D modes.

Standard Model matter fields could be bulk degrees of freedom, not confined to a brane.

Supports alternative localization mechanisms in extra-dimensional models.

Abstract

Recently, Randall and Sundrum proposed a solution to the hierarchy problem where the background spacetime is five dimensional. There are two 3-branes, and the mass scale for fields that propagate on one of the 3-branes is exponentially suppressed relative to the fundamental scale of theory, which is taken to be the Planck mass, M_Pl. In this letter we show that bulk fields with a five dimensional mass term of order M_Pl have, after integrating over the extra dimension, modes with four-dimensional masses that are exponentially suppressed as well. This opens the possibility that in this scenario the Standard Model matter fields may correspond to degrees of freedom that are not confined to a 3-brane.