Moduli stabilization with bulk scalar in nested doubly warped braneworld model

TL;DR

This paper investigates the stabilization of multiple moduli in a six-dimensional doubly warped braneworld model, proposing a mechanism involving a bulk scalar field and higher curvature effects to address the hierarchy problem.

Contribution

It introduces a novel stabilization mechanism for multiple moduli in a nested warped geometry using a single bulk scalar and higher curvature terms, without fine tuning.

Findings

Successful simultaneous stabilization of both moduli.

Generation of a 4D effective potential from a single bulk scalar.

Higher curvature f(R) terms can serve as stabilizing fields.

Abstract

We examine the modulus stabilization mechanism of a warped geometry model with nested warping. Such a model with multiple moduli is known to offer a possible resolution of the fermion mass hierarchy problem in the standard model. A six dimensional doubly warped braneworld model under consideration admits two distinct moduli, with the associated warp factors dynamically generating different physical mass scales on four 3-branes. In order to address the hierarchy problem related to the Higgs mass, both moduli need to be stabilized around their desired values without any extreme fine tuning of parameters. We show that it is possible to stabilize them simultaneously due to the appearence of an effective 4D moduli potential, which is generated by a single bulk scalar field having non-zero VEVs frozen on the 3-branes. We also discuss how the entire mechanism can possibly be understood from a purely gravitational point of view, with higher curvature f(R) contributions in the bulk automatically providing a scalar degree of freedom that can serve as the stabilizing field in the Einstein frame.