Impact of QCD uncertainties on antiproton spectra from dark-matter annihilation

Adil Jueid, Jochem Kip, Roberto Ruiz De Austri, Peter Skands

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Dark-matter particles that annihilate or decay can undergo complex sequences of processes, including strong and electromagnetic radiation, hadronisation, and hadron decays, before particles that are stable on astrophysical time scales are produced. Antiprotons produced in this way may leave footprints in experiments such as AMS-02. Several groups have reported an excess of events in the antiproton flux in the rigidity range of 10-20 GV. However, the theoretical modeling of baryon production is not straightforward and relies in part on phenomenological models in Monte Carlo event generators. In this work, we assess the impact of QCD uncertainties on the spectra of antiprotons from dark-matter annihilation. As a proof-of-principle, we show that for a two-parameter model that depends only on the thermally-averaged annihilation cross section (σv) and the dark-matter mass (Mχ ), QCD uncertainties can affect the best-fit mass by up to ∼14% (with large uncertainties for large DM masses), depending on the choice of Mχ and the annihilation channel (bb¯ or W + W -), and σv by up to ∼10%. For comparison, changes to the underlying diffusion parameters are found to be within 1%-5%, and the results are also quite resilient to the choice of cosmic-ray propagation model. These findings indicate that QCD uncertainties need to be included in future DM analyses. To facilitate full-fledged analyses, we provide the spectra in tabulated form including QCD uncertainties and code snippets to perform mass interpolations and quick DM fits. The code can be found in this GitHub [1] repository.

Original languageEnglish
Article number068
Number of pages14
JournalJournal of Cosmology and Astroparticle Physics
Issue number4
Publication statusPublished - 28 Apr 2023


  • cosmic ray experiments
  • cosmic ray theory
  • dark matter simulations
  • Frequentist statistics

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