Mass Limits on Neutralino Dark Matter

TL;DR

This paper establishes upper mass limits for neutralino dark matter particles within the MSSM framework, based on relic density constraints and gamma-ray observations, highlighting the viability of certain scenarios and their observational implications.

Contribution

It provides the first comprehensive upper mass bounds for neutralino dark matter considering various MSSM scenarios and recent astrophysical data.

Findings

No coannihilation scenario supports dark matter masses above 2.5 TeV for winos.

Higgsino-like particles are limited to masses below 1.8 TeV.

Fine-tuned Higgs resonance scenarios can permit masses up to 34 TeV.

Abstract

We set an upper limit on the mass of a supersymmetric neutralino dark matter particle using the MicrOMEGAS and DarkSUSY software packages and the most recent constraints on relic density from combined WMAP and SDSS data. We explore several different possible scenarios within the MSSM, including coannihilation with charginos and sfermions and annihilation through a massive Higgs resonance, using low energy mass inputs. We find that no coannihilation scenario is consistent with dark matter in observed abundance with a mass greater than 2.5 TeV for a wino--type particle or 1.8 TeV for a Higgsino--type. Contrived scenarios involving Higgs resonances with finely--tuned mass parameters can allow masses as high as 34 TeV. The resulting gamma--ray energy distribution is not in agreement with the recent multi--TeV gamma ray spectrum observed by H.E.S.S. originating from the center of the Milky Way. Our results are relevent only for dark matter densities resulting from a thermal origin.