Ghosts- and Tachyon-Free Regions of the Randall-Sundrum Model Parameter Space

TL;DR

This paper identifies ghost- and tachyon-free parameter regions in the Randall-Sundrum model with bulk fields, enabling the construction of stable and realistic phenomenological models.

Contribution

It precisely delineates the parameter space where bulk mass terms and brane-localized kinetic terms lead to stable, physically consistent Randall-Sundrum models.

Findings

Identified stable regions free from ghosts and tachyons.

Provided criteria for physically acceptable parameter choices.

Facilitated realistic model building within the RS framework.

Abstract

Model building within the Randall-Sundrum (RS) framework generally involves placing the Standard Model fields in the bulk. Such fields may possess non-zero values for their associated brane-localized kinetic terms (BLKTs) in addition to possible bulk mass parameters. In this paper we clearly identify the regions of the RS model parameter space where the presence of bulk mass terms and BLKTs yield a setup which is free from both ghost and tachyon instabilities. Such physically acceptable parameter space regions can then be used to construct realistic and phenomenologically viable RS models.