High Statistics Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–500 GeV with the Alpha Magnetic Spectrometer on the International Space Station

2014/09/18 by L. Accardo, M. Aguilar, D. Aisa +97 · 4 citations
Physics and Astronomy · #Dark Matter and Cosmic Phenomena #Particle Detector Development and Performance #Astrophysics and Cosmic Phenomena

paper · pdf · doi:10.1103/physrevlett.113.121101

openalex publication_date 2014/09/18 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/04

Abstract

A precision measurement by AMS of the positron fraction in primary cosmic rays in the energy range from 0.5 to 500 GeV based on 10.9 million positron and electron events is presented. This measurement extends the energy range of our previous observation and increases its precision. The new results show, for the first time, that above ∼200 GeV the positron fraction no longer exhibits an increase with energy.

Citations

• Pulsars as the sources of high energy cosmic ray positrons
• New Measurement of the Cosmic-Ray Positron Fraction from 5 to 15 GeV
• First Result from the Alpha Magnetic Spectrometer on the International Space Station: Precision Measurement of the Positron Fraction in Primary Cosmic Rays of 0.5–350 GeV
• Geant4 developments and applications
• Astrophysical models for the origin of the positron “excess”
• The role of antimatter searches in the hunt for supersymmetric dark matter
• Boosted decision trees as an alternative to artificial neural networks for particle identification

Cited by

• Electron and Positron Fluxes in Primary Cosmic Rays Measured with the Alpha Magnetic Spectrometer on the International Space Station
• Indirect and direct search for dark matter
• Antimatter [wikipedia]
• Positron [wikipedia]