The cosmological Mass Varying Neutrino model in the late universe

Abstract

The cosmological Mass Varying Neutrino (MaVaN) model is considered, where the interaction between a fermionic field and a scalar field with a Ratra-Peebles potential via a Yukawa coupling is investigated. Observational constraints on the flat and non-flat MaVaN models, as well as on the standard $Λ$CDM model, are derived from 32 $H(z)$ measurements using MCMC analysis. Comparison with the $Λ$CDM model using the criteria $Δχ^2_{\rm min}$, $AICc$, and $BIC$ shows no statistically significant improvement for MaVaN models. Deviations in the expansion history remain well below $1σ$, indicating that the $H(z)$ data alone do not provide sufficient constraining power to distinguish MaVaN models from the $Λ$CDM model. The non-flat MaVaN model reduces the tension between the $H_0$ value inferred from $H(z)$ data and the Planck CMB measurement from $\sim 2σ$ in the $Λ$CDM framework to $\sim 1.1σ$. The discrepancy with the SH0ES measurement of $H_0$ is also reduced to below $1σ$, primarily due to the large uncertainties of the $H(z)$ data.

Figures (6)

• Figure 1: A three-dimensional representation of the Ratra-Peebles potential for $M=2\cdot 10^{-3}$ eV.
• Figure 2: The normalized expansion rate of the universe in the flat MaVaN model, taking into account $N_f=3$, for different values of the model parameter $\alpha$.
• Figure 3: The mutual influence of the sum of neutrino masses and the scalar field Ratra-Peebles potential, for different values of the model parameter $\alpha$.
• Figure 4: The dependence of the mass of the scalar field with the Ratra-Peebles potential on the model parameter $\alpha$.
• Figure 5: Best-fit Hubble parameter values $H(z)$, with $1\sigma$, $2\sigma$, and $3\sigma$ confidence regions, and $1\sigma$ error bars for independent and correlated $H(z)$ data in the flat and non-flat MaVaN models, as well as in the standard $\Lambda$CDM model.