Towards Understanding the Origin of Cosmic-Ray Positrons
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PhysRevLett.122.041102.pdf
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Author(s)
Aguilar, M.
Ali Cavasonza, L.
Ambrosi, G.
Arruda, L.
Attig, N.
Azzarello, P.
Bachlechner, A.
Barao, F.
Barrau, A.
Barrin, L.
Date Issued
January 2019
Journal
Physical Review Letters
Publisher
American Physical Society
Citation
Aguilar, M. et al. "Towards Understanding the Origin of Cosmic-Ray Positrons." Physics Review Letters 122, 4 (February 2019): 041102
Version
Final published version
Abstract
Precision measurements of cosmic ray positrons are presented up to 1 TeV based on 1.9 million positrons collected by the Alpha Magnetic Spectrometer on the International Space Station. The positron flux exhibits complex energy dependence. Its distinctive properties are (a) a significant excess starting from 25.2±1.8 GeV compared to the lower-energy, power-law trend, (b) a sharp dropoff above 284₋₆₄⁺⁹¹ GeV, (c) in the entire energy range the positron flux is well described by the sum of a term associated with the positrons produced in the collision of cosmic rays, which dominates at low energies, and a new source term of positrons, which dominates at high energies, and (d) a finite energy cutoff of the source term of E[superscript s] = 810₋₁₈₀⁺³¹⁰ GeV is established with a significance of more than 4σ. These experimental data on cosmic ray positrons show that, at high energies, they predominantly originate either from dark matter annihilation or from other astrophysical sources.
MIT Department
Massachusetts Institute of Technology. Department of Physics
Massachusetts Institute of Technology. Laboratory for Nuclear Science
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DOI of Published Version
https://doi.org/10.1103/PhysRevLett.122.041102
