Can Dark Matter Decay in Dark Energy?

TL;DR

This paper investigates the thermodynamical possibility of Dark Matter decaying into Dark Energy, finding that such decay is plausible under certain chemical potential conditions and is favored by recent cosmological data.

Contribution

It introduces a thermodynamical framework considering different temperatures and chemical potentials to analyze Dark Matter to Dark Energy decay possibilities.

Findings

Decay from Dark Matter to Dark Energy is possible with non-zero chemical potentials.

Likelihood analysis favors Dark Matter decay with about 93% probability.

The study uses background cosmological data to support the decay scenario.

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 $\mu_x<0$ and $\mu_{dm}=0$ or $\mu_x=0$ and $\mu_{dm}>0$, the decay is possible, where $\mu_x$ and $\mu_{dm}$ 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 $\sim 93%$ over the Dark Energy decay. This result comes from a likelihood analysis where only background evolution has been considered.