2020/01/31 by Rebecca Diesing, Damiano Caprioli · 2 citations
Physics and Astronomy · #Antimatter #Antiparticle #Antiproton #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmic ray #Dark Matter and Cosmic Phenomena #Dark matter #Electron #Flux (metallurgy) #Galaxy #Lepton #Neutrino Physics Research #Nuclear physics #PAMELA detector #Physics #Positron #Proton #Pulsar #Secondary electrons #Ultra-high-energy cosmic ray #astro-ph.HE
paper · pdf · doi:10.1103/physrevd.101.103030
published as Phys. Rev. D 101, 103030 (2020) · 7 pages, 2 figures, accepted for publication in PRD
arxiv created 2020/05/21 · openalex publication_date 2020/05/21 · arxiv updated 2020/05/27 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/06
We investigate the possibility of secondary production as the source of cosmic ray (CR) positrons, taking into account observed electron and antiproton spectra and allowing that the reported steepening in the AMS-02 positron spectrum may be due to radiative losses. Using a simple argument based on the antiproton spectrum, we show that positrons cannot be purely secondary. Namely, the antiproton to positron ratio requires that positrons be uncooled up to a few hundred GeV. This requirement implies that CR protons escape from the Galaxy too quickly to reproduce the observed antiproton flux. We further show that this result rules out also more complex secondary production scenarios such as reacceleration and the Nested Leaky Box. Thus, we conclude that, while antiprotons can be produced exclusively in secondary interactions, a primary source of CR positrons---be it dark matter or pulsars---is required to explain their spectrum.