What could we learn from a sharply falling positron fraction?

Abstract

Recent results from the AMS-02 data have confirmed that the cosmic ray positron fraction increases with energy between 10 and 200GeV. This quantity should not exceed 50%, and it is hence expected that it will either converge towards 50% or fall. We study the possibility that future data may show the positron fraction dropping down abruptly to the level expected with only secondary production, and forecast the implications of such a feature in term of possible injection mechanisms that include both dark matter and pulsars. {Were a sharp steepening to be found, rather surprisingly, we conclude that pulsar models would do at least as well as dark matter scenarios in terms of accounting for any spectral cut-off.

arXiv comment7 pages, 4 figures, matches published version, no change to the conclusions

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Cited by in corpus (11)

• Dark matter vs. astrophysics in the interpretation of AMS-02 electron and positron data
• Dark Matter Search in Space: Combined Analysis of Cosmic Ray Antiproton-to-Proton Flux Ratio and Positron Flux Measured by AMS-02
• Fermi/LAT observations of Dwarf Galaxies highly constrain a Dark Matter Interpretation of Excess Positrons seen in AMS-02, HEAT, and PAMELA
• Multi-messenger constraints to the local emission of cosmic-ray electrons
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• Constraining annihilating dark matter by radio data of M33
• Origin of the DAMPE 1.4 TeV peak
• Indirect constraints on the dark matter interpretation of excess positrons seen by AMS-02
• What can we learn from a sharply falling positron fraction?