23-27 May 2016
Europe/Madrid timezone

Confronting recent AMS-02 positron fraction and Fermi-LAT extragalactic gamma ray background measurements with gravitino dark matter

24 May 2016, 18:10
Contributed talk Astro/Cosmo/Neutrinos Astro-Neutrino 5


Edson Carquin Lopez (USM Valparaiso, Chile)


Recent positron flux fraction measurements in cosmic-rays (CR) made by the AMS-02 detector confirm and extend the evidence on the existence of a new (yet unknown) source of high energy electrons and positrons. We propose the gravitino dark matter with bilinear R-parity violating couplings as this source. We compute the electron, positron and γ -ray fluxes produced by each gravitino decay channel as it would be detected at the Earth’s position. Combining the flux from the different decay modes we are able to reproduce AMS-02 measurements of the positron fraction, as well as the electron and positron fluxes, with a gravitino dark matter mass in the range 1–3 TeV and lifetime of ∼1.0–0.7×1026 s. The high statistics measurement of electron and positron fluxes, and the flattening in the behaviour of the positron fraction recently found by AMS-02 allow us to determine that the preferred gravitino decaying mode by the fit is W ± τ ∓ , unlike previous analyses. Then we study the viability of these scenarios through their implication in γ -ray observations. For this we use the Extragalactic γ -ray Background recently reported by the Fermi-LAT Collaboration and a state-of-the- art model of its known contributors. Based on the γ -ray analysis we exclude the gravitino parameter space which provides an acceptable explanation of the AMS-02 data.

Primary author

Edson Carquin Lopez (USM Valparaiso, Chile)

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