The last refuge of mixed wino-Higgsino dark matter

TL;DR

This paper investigates the parameter space of mixed wino-Higgsino dark matter in the MSSM, considering various astrophysical and cosmological constraints, and finds significant restrictions especially for positive mu parameter.

Contribution

It provides a comprehensive analysis including a complete Sommerfeld effect calculation for mixed-neutralino dark matter, refining the allowed parameter space.

Findings

Most of the parameter space is excluded for μ>0.

A substantial region remains allowed for μ<0 under conservative assumptions.

Constraints from multiple astrophysical observations are combined to restrict dark matter models.

Abstract

We delineate the allowed parameter and mass range for a wino-like dark matter particle containing some Higgsino admixture in the MSSM by analysing the constraints from diffuse gamma-rays from the dwarf spheroidal galaxies, galactic cosmic rays, direct detection and cosmic microwave background anisotropies. A complete calculation of the Sommerfeld effect for the mixed-neutralino case is performed. We find that the combination of direct and indirect searches poses significant restrictions on the thermally produced wino-Higgsino dark matter with correct relic density. For $\mu>0$ nearly the entire parameter space considered is excluded, while for $\mu<0$ a substantial region is still allowed, provided conservative assumptions on astrophysical uncertainties are adopted.