Gravitino Dark Matter

Understand

Gravitino dark matter, together with thermal leptogenesis, implies an upper bound on the masses of superparticles.

• In the case of broken R-parity the constraints from primordial nucleosynthesis are naturally satisfied and decaying gravitinos lead to characteristic signatures in high energy cosmic rays.
• Electron and positron fluxes from gravitino decays cannot explain both, the PAMELA positron fraction and the electron + positron flux recently measured by Fermi LAT.
• The observed fluxes require astrophysical sources.