The neutrino masses and the change of allowed parameter region in universal extra dimension models

TL;DR

This paper explores how the relic abundance of dark matter in universal extra dimension models with right-handed neutrinos is affected by neutrino mass scales, showing the potential for a 500 GeV extra dimension scale consistent with cosmological data.

Contribution

It demonstrates that including right-handed neutrinos in universal extra dimension models alters the dark matter relic abundance and allows for a lower extra dimension scale compatible with observations.

Findings

Dark matter relic abundance can significantly change with large neutrino masses.

The extra dimension scale can be as low as 500 GeV in the minimal model.

Models with right-handed neutrinos avoid the KK graviton problem.

Abstract

Relic abundance of dark matter is investigated in the framework of universal extra dimension models with right-handed neutrinos. These models are free from the serious Kaluza-Klein (KK) graviton problem that the original universal extra dimension model possesses. The first KK particle of the right-handed neutrino is a candidate for dark matter in this framework. When ordinary neutrino masses are large enough such as the degenerate mass spectrum case, the dark matter relic abundance can change significantly. The scale of the extra dimension consistent with cosmological observations can be 500 GeV in the minimal setup of universal extra dimension models with right-handed neutrinos.