Towards an hybrid compactification with a scalar-tensor global cosmic string

TL;DR

This paper constructs a six-dimensional braneworld model with a global cosmic string, exploring its geometric properties and implications for the hierarchy problem within a string theory framework.

Contribution

It presents a new six-dimensional solution involving a warped brane and a noncompact extra dimension derived from a scalar-tensor cosmic string in string theory.

Findings

The model features a power law warp factor and a noncompact extra dimension.

Parameter ranges are identified where the hierarchy problem remains unsolved.

The Brans-Dicke parameter can influence the smoothing of the hierarchy problem.

Abstract

We derive a solution of the gravitational equations which leads to a braneworld scenario in six dimensions using a global cosmic string solution in a low energy effective string theory framework. The final spacetime is composed by one warped brane with $\mathbb{R}^{(3,1)}\times S^{1}$ topology and a power law warp factor, and one noncompact extra dimension transverse to the brane. By looking at the current experimental bounds, we find a range of parameters in which, if the on-brane dimension has an acceptable size, it does not solve the hierarchy problem. In another example this problem is smoothed by the Brans-Dicke parameter.