Probing Gravitino Dark Matter with PAMELA and Fermi

Understand

We analyze the cosmic-ray signatures of decaying gravitino dark matter in a model independent way based on an operator analysis.

• Thermal leptogenesis and universal boundary conditions at the GUT scale restrict the gravitino mass to be below 600 GeV.
• Electron and positron fluxes from gravitino decays, together with the standard GALPROP background, cannot explain both, the PAMELA positron fraction and the electron + positron flux recently measured by Fermi LAT.
• For gravitino dark matter, the observed fluxes require astrophysical sources.