Impact of a nearby subhalo on the constraint of dark matter annihilation from cosmic ray antiprotons

TL;DR

This paper examines how a hypothetical nearby dark matter subhalo could influence constraints on dark matter annihilation cross sections derived from cosmic ray antiproton data, considering various models and current experimental results.

Contribution

It introduces a method to evaluate the impact of a nearby subhalo on dark matter annihilation constraints using cosmic-ray antiproton spectra and considers different subhalo models.

Findings

Current AMS-02 data do not constrain the contribution from a nearby subhalo.

The presence of a nearby subhalo can significantly alter the upper limits on dark matter annihilation cross sections.

The impact depends on the subhalo's concentration model and probability distribution.

Abstract

Numerous simulations indicate that a large number of subhalos should be hosted by the Milky Way. The potential existence of a nearby subhalo could have important implications for our understanding of dark matter (DM) annihilation. In this study, we investigate the hypothetical presence of a nearby subhalo and set the upper limits on the DM annihilation cross section by analyzing the cosmic-ray antiproton spectrum. By presenting the ratios of annihilation cross section limits for scenarios with and without a nearby subhalo, we can quantitatively evaluate the potential impact of the nearby subhalo on the limits of the DM annihilation cross section. The impacts of the concentration model and the subhalo probability distribution have been considered. We explore the antiproton contribution of the potential nearby DM subhalo accounting for the DAMPE $e^\pm$ spectrum at $\sim 1.4$ TeV and find that the current AMS-02 antiproton results do not place the constraint on this contribution.