Probing the interaction between dark matter and dark energy in the presence of massive neutrinos

TL;DR

This paper probes dark sector interactions between dark matter and dark energy in the presence of massive neutrinos, using Planck 2015 CMB data combined with JLA, BAO, CC, and local $H_0$ measurements. The authors implement a coupling $Q=\delta H \rho_{\rm dm}$ with a constant equation-of-state parameter $w$ and analyze three neutrino configurations: three active neutrinos, active neutrinos with $N_{\rm eff}$ free, and one sterile neutrino with $N_{\rm eff}=4.046$ and $m_{\nu_s}$. They find no evidence for coupling in Models I and II, but a nonzero coupling $0.0002 \le \delta \le 0.0045$ at 2$\sigma$ in Model III, with $m_{\nu_s}<0.40$–$0.48$ eV and $H_0 \approx 73$ km s$^{-1}$ Mpc$^{-1}$, suggesting the sterile neutrino scenario could simultaneously accommodate a DM-DE interaction and alleviate the $H_0$ tension. The work highlights the potential of sterile neutrinos to influence dark sector dynamics and emphasizes the value of combining CMB with late-time probes to test beyond-$\Lambda$CDM physics.

Abstract

We consider the possibility of an interaction in the dark sector in the presence of massive neutrinos, and study the observational constraints on three different scenarios of massive neutrinos using the most recent CMB anisotropy data in combination with type Ia supernovae, baryon acoustic oscillations, and Hubble parameter measurements. When a sterile neutrino is introduced in the interacting dark sector scenario in addition to the standard model prediction of neutrinos, we find that the coupling parameter, characterizing the interaction between dark matter and dark energy, is non-zero at 2$σ$ confidence level. The interaction model with sterile neutrino is also found to be a promising one to alleviate the current tension on Hubble constant. We do not find the evidence for a coupling in the dark sector when the possibility of a sterile neutrino is discarded.

Figures (4)

• Figure 1: The figure shows the theoretical predictions for angular power spectrum of the CMB temperature anisotropy for some specific values of the dark sector coupling parameter $\delta$, where the other parameters are fixed to their mean values given in table \ref{['tab1']}.
• Figure 2: One-dimensional marginalized distribution, and 1$\sigma$ and 2$\sigma$ two-dimensional confidence contours for some selected parameters of the Model I.
• Figure 3: One-dimensional marginalized distribution, and 1$\sigma$ and 2$\sigma$ two-dimensional confidence contours for some selected parameters of the Model II.
• Figure 4: One-dimensional marginalized distribution, and 1$\sigma$ and 2$\sigma$ two-dimensional confidence contours for some selected parameters of the Model III.