Wino Dark Matter in light of the AMS-02 2015 Data

TL;DR

This paper investigates whether wino dark matter can explain the AMS-02 observed antiproton to proton ratio, finding that a 2.5-3 TeV wino can fit the data well and predicting a decrease at higher energies.

Contribution

It demonstrates that wino dark matter with a mass around 3 TeV can account for the AMS-02 antiproton data better than astrophysical models alone.

Findings

Wino annihilation flux fits AMS-02 data for 2.5-3 TeV mass range.

Thermal wino dark matter at ~3 TeV provides a particularly good fit.

Predicted decrease in antiproton ratio at hundreds of GeV energy, testable by future data.

Abstract

The AMS-02 collaboration has recently reported the antiproton to proton ratio with improved accuracy. In view of uncertainties of the production and the propagation of the cosmic rays, the observed ratio is still consistent with the secondary astrophysical antiproton to proton ratio. However, it is nonetheless enticing to examine whether the observed spectrum can be explained by a strongly motivated dark matter, the wino dark matter. As we will show, we find that the antiproton flux from the wino annihilation can explain the observed spectrum well for its mass range 2.5-3 TeV. The fit to data becomes particularly well compared to the case without the annihilation for the thermal wino dark matter case with a mass about 3 TeV. The ratio is predicted to be quickly decreased at the energy several hundreds of GeV, if this possibility is true, and it will be confirmed or ruled out in near future when the AMS-02 experiment accumulates enough data at this higher energy region.