A fussy revisitation of antiprotons as a tool for Dark Matter searches

TL;DR

This paper thoroughly revisits the modeling of antiprotons as a tool for Dark Matter detection, emphasizing detailed astrophysical effects and updating flux data to refine constraints on Dark Matter contributions.

Contribution

It provides a comprehensive reanalysis of antiproton fluxes including detailed propagation effects and updated experimental data, leading to more accurate constraints on Dark Matter.

Findings

No clear excess of antiprotons indicating Dark Matter

Preference for a flatter diffusion coefficient energy dependence

Stricter constraints on Galactic Dark Matter annihilation

Abstract

Antiprotons are regarded as a powerful probe for Dark Matter (DM) indirect detection and indeed current data from \PAMELA\ have been shown to lead to stringent constraints. However, in order to exploit their constraining/discovery power properly, great attention must be put into effects (linked to their propagation in the Galaxy) which may be perceived as subleading but actually prove to be quite relevant. We revisit the computation of the astrophysical background and of the DM antiproton fluxes fully including the effects of: diffusive reacceleration, energy losses including tertiary component and solar modulation (in a force field approximation). Using the updated proton and helium fluxes just released by the \AMS\ experiment we reevaluate the secondary astrophysical antiproton to proton ratio and its uncertainties, and compare it with the ratio preliminarly reported by \AMS. We find no unambiguous evidence for a significant excess with respect to expectations. Yet, some preference for a flatter energy dependence of the diffusion coefficient (with respect to the {\sc Med} benchmark often used in the literature) starts to emerge. Finally, we provide a first assessment of the room left for exotic components such as Galactic Dark Matter annihilation, deriving new stringent constraints.