Gravity localization and mass hierarchy in scalar-tensor branes

TL;DR

This paper explores a scalar-tensor braneworld model that addresses the mass hierarchy problem by confining our universe to a positive tension brane, revealing a tiny mass spectrum spacing and weakly interacting light gravitons.

Contribution

It introduces a scalar-tensor gravity framework for braneworlds that solves the hierarchy problem with a positive tension brane and analyzes the graviton spectrum and interactions.

Findings

Mass spectrum spacing is very tiny.

Light gravitons have weak interactions, making them unobservable in colliders.

Confinement on positive tension brane is crucial for correct cosmological equations.

Abstract

We consider a braneworld model in the scalar-tensor gravity. In order to solve the gauge hierarchy problem in this model, our world should be confined on the positive tension brane rather than on the negative one. This is crucial to reproduce a correct Friedmann-like equation on the brane. Interestingly, it is found that the spacing of mass spectrum in this scenario is very tiny, but the light gravitons cannot be observed individually in colliders because of their sufficiently weak interaction with matter fields on the visible brane.