The role of higher derivative bulk scalar in stabilizing a warped spacetime

The absence, so far, of any graviton signatures at the LHC imposes severe constraints on the Randall-Sundrum scenario. Although a generalization to higher dimensions with nested warpings has been shown to avoid these constraints, apart from incorporating several other phenomenologically interesting features, moduli stabilization in such models has been an open question. We demonstrate here how both the moduli involved can be stabilized, employing slightly different mechanisms...

A recent work has investigated the possibility that the mass scale for the ultraviolet (UV) brane in the Randall-Sundrum (RS) model is of the order 10^3 TeV. In this so called ``Little Randall-Sundrum'' (LRS) model the bounds on the gauge sector are less severe, permitting a lower Kaluza-Klein scale and cleaner discovery channels. However employing a low UV scale nullifies one major appeal of the RS model; namely the elegant explanation of the hierarchy between the Planck and...

Basic idea of Randall-Sundrum brane world model I and II is reviewed with detailed calculation. After introducing the brane world metric with exponential warp factor, metrics of Randall-Sundrum models are constructed. We explain how Randall-Sundrum model I with two branes makes the gauge hierarchy problem much milder, and then derive Newtonian gravity in Randall-Sundrum model II with a single brane by considering small fluctuations.

In generalized Randall-Sundrum (RS) model with dilaton where bulk potential is generated by the antisymmetric tensor field the mass term of this field is introduced into the brane's Action. This permits to stabilize brane's position and hence to calculate the Planck/electroweek scales ratio which proves to depend non-analytically on the dilaton-antisymmetric tensor field coupling constant. The large observed number of mass hierarchy is achieved for the moderate value of this ...

In the warped space model, the inter-brane distance can be stabilized by the Goldberger-Wise mechanism. Of particular importance, the stabilization potential calls for a proper identification of the dynamical degree of freedom. In this paper, we provided a complete calculation of the effective Lagrangian till the quadratic order that is generic for the Randall-Sundrum model and its $N$-brane $(N \geq 4)$ extensions. By applying the variation principle to a specific perturbati...

In this work we explore an alternative to the central point of the Randall-Sundrum brane world scenario, namely, the particular nonfactorizable metric, in order to solve the hierarchy problem. From a topological viewpoint, we show that the exponential factor, crucial in the Randall-Sundrum model, appears in our approach, only due to the brane existence instead of a special metric background. Our results are based in a topological gravity theory via a non-standard interaction ...

We investigate a scenario with two four-branes embedded in six dimensions. When the metric is periodic and compact in one of the dimensions parallel to the branes, the value of the effective cosmological constant for the remaining five dimensions can assume a variety of values, determined by the dependence of the metric on the sixth dimension. The picture that emerges resembles the Randall-Sundrum model but with an extra warped dimension that allows the usual brane-bulk fine ...

We investigate aspects of cosmology in brane world theories with a bulk scalar field. We concentrate on a recent model motivated from supergravity in singular spaces. After discussing the background evolution of such a brane-world, we present the evolution of the density contrast. We compare our results to those obtained in the (second) Randall-Sundrum scenario and usual 4D scalar-tensor theories.

This work sets up a general theoretical framework to study stability of models with a warped extra dimension where N scalar fields couple minimally to gravity. Our analysis encompasses Randall-Sundrum models with branes and bulk scalars, and general domain-wall models. We derive the Schrodinger equation governing the spin-0 spectrum of perturbations of such a system. This result is specialized to potentials generated using fake supergravity, and we show that models without br...

We review a viable alternative scenario of the inflationary universe in the context of the Randall-Sundrum (RS) braneworld. In this scenario, the dynamics of a 5-dimensional scalar field, which we call a bulk scalar field, plays the central role. Focusing on the second (single-brane) RS model, we discuss braneworld inflation driven by a bulk scalar field without introducing an inflaton on the brane. As a toy model, for the bulk scalar field, we consider a minimally coupled ma...