SuperWIMP Dark Matter in Supergravity with a Gravitino
  We investigate the superWIMP scenario in the framework of supersymmetry, in which the lightest supersymmetric particle is a stable gravitino. We consider slepton, sneutrino or neutralino being the next-lightest supersymmetric particle, and determine what superpartner masses are viable, applying cosmic-microwave background and electromagnetic and hadronic Big-Bang Nucleosythesis constraints. 
Jonathan L. Feng, Shufang Su, Fumihiro Takayama