Wino Dark Matter Under Siege

TL;DR

This paper evaluates the constraints on wino dark matter from indirect detection experiments, showing that current gamma-ray observations exclude certain mass ranges and scenarios, significantly impacting supersymmetric models.

Contribution

It provides the first comprehensive analysis of indirect detection limits on wino dark matter across different scenarios and halo models, highlighting the exclusion of non-thermal winos.

Findings

H.E.S.S. excludes 3.1 TeV thermal wino

Combined H.E.S.S. and Fermi exclude non-thermal scenario

Uncertainties in exclusions are thoroughly analyzed

Abstract

A fermion triplet of SU(2)_L - a wino - is a well-motivated dark matter candidate. This work shows that present-day wino annihilations are constrained by indirect detection experiments, with the strongest limits coming from H.E.S.S. and Fermi. The bounds on wino dark matter are presented as a function of mass for two scenarios: thermal (winos constitute a subdominant component of the dark matter for masses less than 3.1 TeV) and non-thermal (winos comprise all the dark matter). Assuming the NFW halo model, the H.E.S.S. search for gamma-ray lines excludes the 3.1 TeV thermal wino; the combined H.E.S.S. and Fermi results completely exclude the non-thermal scenario. Uncertainties in the exclusions are explored. Indirect detection may provide the only probe for models of anomaly plus gravity mediation where the wino is the lightest superpartner and scalars reside at the 100 TeV scale.