Speaker
Description
Several studies have pointed out an excess in the AMS-02 antiproton spectrum at rigidities of 10–20 GV. Its spectral properties were found to be consistent with a dark-matter particle of mass 50–100 GeV which annihilates hadronically at roughly the thermal rate. Here, we reinvestigate the antiproton excess, including all relevant sources of systematic errors. Most importantly, we perform a realistic estimate of the correlations in the AMS-02 systematic error which could potentially “fake” a dark-matter signal. The dominant systematics in the relevant rigidity range originate from uncertainties in the cross sections for absorption of cosmic rays within the detector material. We calculate their correlations within the Glauber-Gribov theory of inelastic scattering. The AMS-02 correlations enter our spectral search for dark matter in the form of covariance matrices. Remarkably, the consideration of all uncertainties eliminates the statistical preference for an additional contribution from dark matter. While these findings cast severe doubts on the robustness of the excess, the situation is not fully conclusive. Correlated uncertainties in the ‘effective acceptance’ and the modeling of the diffusion coefficient at low energies also play an important role.
Keywords
Cosmic rays; dark matter; AMS-02; nuclear cross sections;
| Subcategory | Theoretical Results |
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