Towards Understanding the Origin of Cosmic-Ray Positrons.
Phys Rev Lett
; 122(4): 041102, 2019 Feb 01.
Article
em En
| MEDLINE
| ID: mdl-30768313
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_{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.
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MEDLINE
Idioma:
En
Revista:
Phys Rev Lett
Ano de publicação:
2019
Tipo de documento:
Article
País de afiliação:
Espanha