A novel braneworld model with a bulk scalar field

We consider a new braneworld model with a bulk scalar field coupled to gravity. The bulk scalar action is inspired by the proposed low energy effective action around the tachyon vacuum. A class of warped geometries representing solutions of this Einstein-scalar system for a specific scalar potential is found. The geometry is non singular with a decaying warp factor and a negative Ricci curvature. The solution of the hierarchy problem is obtained using this type of warping. Though qualitatively similar to the usual Randall-Sundrum I model there are interesting quantitative differences. Additionally, in the RS II set-up the graviton zero mode as well as spin-half massless fermions are found to be localised on the brane. (c) 2005 Elsevier B.V. All rights reserved.