Limits on the integration constant of the dark radiation term in Brane Cosmology

TL;DR

This paper constrains the possible contribution of dark radiation in brane-world cosmology using primordial Helium abundance data, limiting the integration constant to a specific range.

Contribution

It provides the first semi-analytical bounds on the dark radiation integration constant in brane cosmology from primordial nucleosynthesis constraints.

Findings

The integration constant is limited to between -8.9 and 2.2.

Dark radiation contribution is constrained to about -27% to 7% of photon energy density.

The method used is simple, approximate, and semi-analytical.

Abstract

We consider the constraints from primordial Helium abundances on the constant of integration of the dark radiation term of the brane-world generalized Friedmann equation derived from the Randall-Sundrum Single brane model. We found that -- using simple, approximate and semianalytical Method -- that the constant of integration is limited to be between -8.9 and 2.2 which limits the possible contribution from dark radiation term to be approximately between -27% to 7% of the background photon energy density.