Selftuning and its footprints

TL;DR

This paper examines the limitations of self-tuning mechanisms in brane world models, highlighting how changes in brane tension affect physical constants and the stability of extra dimensions.

Contribution

It provides a detailed analysis of the conflict between self-tuning and stabilization mechanisms in six-dimensional brane models.

Findings

Self tuning models are sensitive to brane tension changes.

Compactification volume varies with brane tension modifications.

Self tuning and stabilization mechanisms are often incompatible.

Abstract

We re-consider the self tuning idea in brane world models of finite volume. We notice that in a large class of self tuning models, the four dimensional physics is sensitive to the vacuum energy on the brane. In particular the compactification volume changes each time the tension of the brane is modified: consequently, observable constants, as the effective Planck mass or masses of matter fields, change as well. We notice that the self tuning mechanism and the stabilization mechanism of the size of the extra dimensions are generically in apparent conflict. We focus on a self tuning model in six spacetime dimensions to analyze how the above considerations are explicitely realized.