Testing Astrophysical Models for the PAMELA Positron Excess with Cosmic Ray Nuclei

2009/05/31 by Philipp Mertsch, S. Sarkar, Subir Sarkar · 3 citations
Physics and Astronomy · #Annihilation #Antiparticle #Astrophysics #Astrophysics and Cosmic Phenomena #Cosmic ray #Dark Matter and Cosmic Phenomena #Dark matter #Electron #Galaxy #Hadron #Lepton #Nuclear physics #Particle physics theoretical and experimental studies #Physics #Pion #Positron #Pulsar #astro-ph.HE #hep-ph

paper · pdf · doi:10.1103/physrevlett.103.081104

published as Phys.Rev.Lett.103:081104,2009 · 4 pages, 2 figures (RevTex4); revised to include additional data in figures and references; accepted for publication in PRL

arxiv created 2009/07/30 · openalex publication_date 2009/08/21 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/08/05

Abstract

The excess in the positron fraction measured by PAMELA has been interpreted as due to annihilation or decay of dark matter in the Galaxy. More prosaically it has been ascribed to direct production of positrons by nearby pulsars or due to pion production during diffusive shock acceleration of hadronic cosmic rays in nearby sources. We point out that measurements of secondary cosmic ray nuclei can discriminate between these possibilities. New data on the titanium-to-iron ratio support the hadronic source model above and enable a prediction for the boron-to-carbon ratio at energies above 100 GeV.

Citations

• PAMELA data and leptonically decaying dark matter
• TeV Gamma Rays from Geminga and the Origin of the GeV Positron Excess
• Pulsars as the sources of high energy cosmic ray positrons
• Particle acceleration at astrophysical shocks: A theory of cosmic ray origin
• An anomalous positron abundance in cosmic rays with energies 1.5–100 GeV
• Leptophilic dark matter
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• Energy dependence of Ti/Fe ratio in the Galactic cosmic rays measured by the ATIC-2 experiment

Cited by

• Cosmic ray signatures of a 2–3 Myr old local supernova
• Galactic factories of cosmic-ray electrons and positrons
• Implications of the AMS-02 positron fraction in cosmic rays