Evolution of scalar field resonances in a braneworld

TL;DR

This paper numerically studies the evolution of massive scalar field resonances in a thick brane scenario, revealing long-lived Kaluza-Klein modes that could serve as dark matter candidates.

Contribution

It derives the evolution equations for scalar fields in a braneworld and demonstrates the existence of long-lived resonant modes through numerical simulations.

Findings

Long-lived scalar KK resonances exist on the brane.

Resonances could be potential dark matter candidates.

Numerical evolution confirms the stability of these modes.

Abstract

In this work, we investigate numerical evolution of massive Kaluza-Klein (KK) modes of a scalar field in a thick brane. We derive the Klein-Gordon equation in five dimensional spacetime, and obtain the evolution equation and the Schr\"odinger-like equation. With the resonances of the scalar KK modes as the initial data, the scalar field is evolved with the maximally dissipative boundary condition. The results show that there are scalar KK resonant particles with long life on the brane, which indicates that these resonances might be viewed as one of the candidates for dark matter.