Can Dark Matter Decay in Dark Energy?
Abstract
We analyze the interaction between Dark Energy and Dark Matter from a thermodynamical perspective. By assuming they have different temperatures, we study the possibility of occurring a decay from Dark Matter into Dark Energy, characterized by a negative parameter Q. We find that, if at least one of the fluids has non vanishing chemical potential, for instance μx<0 and μdm=0 or μx=0 and μdm>0, the decay is possible, where μx and μdm are the chemical potentials of Dark Energy and Dark Matter, respectively. Using recent cosmological data, we find that, for a fairly simple interaction, the Dark Matter decay is favored with a probability of 93% over the Dark Energy decay. This result comes from a likelihood analysis where only background evolution has been considered.