Kinetic Model for Dark Energy - Dark Matter Interaction: Scenario for the Hubble Tension

Abstract

We analyze a model for Dark Energy - Dark Matter interaction, based on a decaying process of the former into the latter. The dynamical equations are constructed following a kinetic formulation, which separates the interacting fluctuations from an equilibrium distribution of both species. The emerging dynamical picture consists of coupled equations, which are specialized in the case of a Dark Energy equation of state parameter; we deal with a modified Lambda Cold Dark Matter ($\Lambda$CDM) model, which is investigated versus a possible interpretation of the Hubble tension. Using an optimized set of the model's free parameters, it can be shown that the obtained Hubble parameter can, in principle, address the tension. We then use the most recent datasets from late Universe sources and compressed information from the Cosmic Microwave Background data to constrain the free parameters and compare the addressed scenario to the standard $\Lambda$CDM model. The study outlines how our proposal is preferred by the data in all cases, based on fit quality, while also alleviating the tension.