Testing astrophysical models for the PAMELA positron excess with cosmic ray nuclei

Abstract

The excess in the positron fraction reported by the PAMELA collaboration 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 stochastic acceleration of hadronic cosmic rays in nearby sources. We point out that measurements of secondary nuclei produced by cosmic ray spallation can discriminate between these possibilities. New data on the titanium-to-iron ratio from the ATIC-2 experiment support the hadronic source model above and enable a prediction to be made for the boron-to-carbon ratio at energies above 100 GeV. Presently, all cosmic ray data are consistent with the positron excess being astrophysical in origin.

4 pages, 2 figures (RevTex4); revised to include additional data in figures and references; accepted for publication in PRL

References in corpus (7)

• Observation of an anomalous positron abundance in the cosmic radiation
• A new measurement of the antiproton-to-proton flux ratio up to 100 GeV in the cosmic radiation
• The origin of the positron excess in cosmic rays
• Decaying Dark Matter can explain the electron/positron excesses
• Measurements of cosmic-ray secondary nuclei at high energies with the first flight of the CREAM balloon-borne experiment
• PAMELA data and leptonically decaying dark matter
• Cosmic ray diffusion near the Bohm limit in the Cassiopeia A supernova remnant

Cited by in corpus (12)

• Galactic electrons and positrons at the Earth:new estimate of the primary and secondary fluxes
• The Connection Between the Positron Fraction Anomaly and the Spectral Features in Galactic Cosmic-Ray Hadrons
• Secondary Cosmic Ray Nuclei from Supernova Remnants and Constraints to the Propagation Parameters
• Discriminating the source of high-energy positrons with AMS-02
• Charge Asymmetric Cosmic Ray Signals From Dark Matter Decay
• On the spectrum of stable secondary nuclei in cosmic rays
• "Discrepant hardenings" in cosmic ray spectra: a first estimate of the effects on secondary antiproton and diffuse gamma-ray yields
• Plus Charge Prevalence in Cosmic Rays: Room for Dark Matter in the Positron Spectrum
• B/C ratio and the PAMELA positron excess
• Dark Stars and Boosted Dark Matter Annihilation Rates
• Cosmic ray backgrounds for dark matter indirect detection
• Antimatter spectra from a time-dependent modeling of supernova remnants