Revisiting the AMS-02 antiproton excess: The role of correlated errors. (arXiv:2107.14606v1 [astro-ph.HE])
<a href="http://arxiv.org/find/astro-ph/1/au:+Heisig_J/0/1/0/all/0/1">Jan Heisig</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Korsmeier_M/0/1/0/all/0/1">Michael Korsmeier</a>, <a href="http://arxiv.org/find/astro-ph/1/au:+Winkler_M/0/1/0/all/0/1">Martin Wolfgang Winkler</a>
Cosmic-ray antiprotons are a remarkable diagnostic tool for the study of
astroparticle physics’ processes in our Galaxy. While the bulk of measured
antiprotons is consistent with a secondary origin, several studies have found
evidence for a subdominant primary component in the AMS-02 data. In this
proceedings article, we revisit the excess considering systematic errors that
could affect the signal. Of particular importance are unknown correlations in
the AMS-02 systematic errors, the dominant of which are associated with the
cross sections for cosmic-ray absorption in the detector. We compute their
correlations in a careful reevaluation of nuclear scattering data, utilizing
the Glauber-Gribov theory to introduce a welcomed redundancy that we explore in
a global fit. The inclusion of correlated errors has a dramatic effect on the
significance of the signal. In particular, the analysis becomes more sensitive
to the diffusion model at low rigidities. For a minimal extension beyond
single-power-law diffusion, the global significance drops below 1$sigma$
severely questioning the robustness of the finding.
Cosmic-ray antiprotons are a remarkable diagnostic tool for the study of
astroparticle physics’ processes in our Galaxy. While the bulk of measured
antiprotons is consistent with a secondary origin, several studies have found
evidence for a subdominant primary component in the AMS-02 data. In this
proceedings article, we revisit the excess considering systematic errors that
could affect the signal. Of particular importance are unknown correlations in
the AMS-02 systematic errors, the dominant of which are associated with the
cross sections for cosmic-ray absorption in the detector. We compute their
correlations in a careful reevaluation of nuclear scattering data, utilizing
the Glauber-Gribov theory to introduce a welcomed redundancy that we explore in
a global fit. The inclusion of correlated errors has a dramatic effect on the
significance of the signal. In particular, the analysis becomes more sensitive
to the diffusion model at low rigidities. For a minimal extension beyond
single-power-law diffusion, the global significance drops below 1$sigma$
severely questioning the robustness of the finding.
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