Non-Compact $AdS_5$ Universe with Parallel Positive Tension 3-Branes

TL;DR

This paper develops a general model with parallel positive tension 3-branes in higher-dimensional space, showing how to generate the 4D Planck scale from a lower GUT scale and providing solutions to the gauge hierarchy problem.

Contribution

It introduces a comprehensive framework with positive tension branes and demonstrates how to naturally produce the 4D Planck scale from a lower GUT scale.

Findings

The 5D GUT scale can be identified with the 5D Planck scale on each brane.

The 4D Planck scale is exponentially generated from a low GUT scale.

Two explicit models illustrate solutions to the gauge hierarchy problem.

Abstract

We construct the general model with only parallel positive tension 3-branes on $M^4 \times R^1$ and $M^4 \times R^1/Z_2$. The cosmology constant is sectional constant along the fifth dimension. In this general scenario, the 5-dimensional GUT scale on each brane can be indentified as the 5-dimensional Planck scale, but, the 4-dimensional Planck scale is generated from the low 4-dimensional GUT scale exponentially in our world. We also give two simple models to show explicitly how to solve the gauge hierarchy problem.