Article,
Gravitational Kaluza-Klein modes in the string-cigar braneworld
PHYSICAL REVIEW D, (2015)
DOI: 10.1103/PhysRevD.91.065031
Abstract
In this work we analyze the properties of the gravitational Kaluza-Klein
(KK) modes in two stringlike braneworlds, the thin
Gherghetta-Shaposhnikov (GS) model and the thick string-cigar model. The
string-cigar model is a smooth generalization of the GS model that
undergoes a Ricci geometrical flow. We find a new massless mode in both
models satisfying the respective Schrodinger equations. By means of a
numerical analysis, we obtain the complete graviton spectrum and its
respective eigenfunctions. The KK spectrum exhibits the usual linear
regime for large discrete index n and we find a new decreasing regime
for small n. Moreover, there is an asymmetric mass gap between the
massless mode and the massive KK tower. The mass gap in the GS model is
bigger than in the string-cigar model. In addition, the mass gap remains
invariant upon the geometrical flow. It turns out that in the
string-cigar model the brane structure smoothes and amplifies the KK
modes near the brane core. The presence of a potential well in the
string-cigar scenario allows the existence of resonant massive gravitons
for small masses.
