Constraints on mSUGRA through entropy and abundance criteria

TL;DR

This paper derives entropy-based constraints on mSUGRA dark matter models using halo and relic abundance data, narrowing down viable parameter regions and establishing a lower neutralino mass bound.

Contribution

It introduces a novel entropy comparison method to constrain mSUGRA parameters using observational relic density data and abundance criteria.

Findings

Small tan beta values are disfavored for positive mu.

Only tan beta around 50 satisfies both criteria within WMAP bounds.

Neutralino mass is constrained to be greater than 151 GeV.

Abstract

We derive an expression for the entropy of a present dark matter halo described by a Navarro-Frenk-White modified model with a central core. The comparison of this entropy with the one of the halo at the freeze-out era allows us to obtain an expression for the relic abundance of neutralinos, which in turn is used to constrain the parameter space in mSUGRA models, when used with the WMAP observations. Moreover, by joning these results with the ones obtained from the usual abundance criteria, we are able to clearly discriminate validity regions among tan beta values of the mSUGRA model, by demanding both criteria to be consistent with the 2 sigma bounds of the WMAP observations for the relic density: 0.112 < Omega h^2 < 0.122. We found that for sign mu positive, small values of tan beta are not favored; only for tan beta ~ 50 are both criteria significantly consistent. The use of both criteria also allows us to put a lower bound on the neutralino mass of > 151 GeV.