Constraints on the extra dimension from KK gravitino decay

TL;DR

This paper investigates how the decay of heavy gravitinos into neutralino dark matter constrains the size of extra dimensions and the reheating temperature in a five-dimensional supergravity model.

Contribution

It introduces a model linking extra dimension size and reheating temperature constraints based on gravitino decay and dark matter abundance.

Findings

Constraints between extra dimension size and reheating temperature.

Dark matter abundance compatible with observations.

Decay of KK gravitinos influences early universe parameters.

Abstract

We study the consequences of the gravitino decay into dark matter. We suppose that the lightest neutralino is the main component of dark matter. In our framework gravitino is heavy enough to decay before Big Bang Nucleosynthesis starts. We consider a model coming from a five dimensional supergravity compactified on $S^1/Z_2$ with gravity in the bulk and matter localized on tensionless branes at the orbifold fixed points. We require that the dark matter, which is produced thermally and in the decay of Kaluza-Klein modes of gravitino, has an abundance compatible with observation. We deduce from our model that there are curves of constraints between the size of the extra-dimension and the reheating temperature of the universe after inflation. This talk is based on hep-ph/0702183 to be published in \PRD.