Constraining the mSUGRA parameter space using the entropy of dark matter halos

TL;DR

This paper introduces a novel method to constrain mSUGRA dark matter models by comparing the entropy of dark matter halos with the freeze-out era, refining parameter space and identifying viable tanβ values.

Contribution

It derives an entropy expression for dark matter halos and combines it with abundance constraints to better restrict mSUGRA parameters, especially tanβ and neutralino mass.

Findings

Small tanβ values are disfavored in the explored parameter space.

Only tanβ around 50 satisfies both entropy and abundance criteria.

A lower bound of 141 GeV is established for the neutralino mass.

Abstract

We derive an expression for the entropy of a dark matter halo described by a Navarro-Frenk-White model with a core. The comparison of this entropy with the one of dark matter at the freeze-out era allows us to constraint the parameter space in mSUGRA models. Moreover, joining these constraints with the ones obtained from the usual abundance criteria and demanding both criteria to be consistent with the 2$\sigma$ bounds for the abundance of dark matter: $0.112\leq\Omega_{DM}h^2\leq0.122$, we are able to clearly discriminate validity regions among the values of $\tan \beta$, one of the parameters of the mSUGRA model. We found that for the explored regions of the parameter space, small values of tan$\beta$ are not favored; only for tan$\beta\simeq50$ are both criteria significantly consistent. In the region where both criteria are consistent we also found a lower bound for the neutralino mass, $m_{\chi}\geq 141$ GeV.