Understand
Since the gravitational interaction is universal, any particle that ever existed, if kinematically accessible, has to be produced through her.
- We explore the possibility that dark matter is generated purely from gravitational scatterings together with heavy Majorana right-handed neutrinos that are long-lived.
- Their late decay could inject significant entropy into the thermal bath, diluting both the dark matter abundance and the cosmic baryon asymmetry, thereby imposing various constraints on the reheating dynamics.
- Additionally to the entropy injection, long-lived right-handed neutrinos could also be responsible for generating the baryon asymmetry through leptogenesis, and hence establish some nontrivial relations between the dark matter and the right-handed properties, and the reheating dynamics