Cosmological evolution of thermal relic particles in f (R) gravity

By considering f (R) gravity models, the cosmic evolution is modified with respect to the standard ACDM scenario. In particular, the thermal history of particles results is modified. In this paper, we derive the evolution of relics particles (weakly interacting massive particles) assuming a reliable f (R) cosmological solution and taking into account observational constraints. The connection to the PAMELA experiment is also discussed. Results are consistent with constraints coming from BICEP2 and PLANCK experiments.