The cosmological Mass Varying Neutrino model in the late universe

TL;DR

This study investigates Mass Varying Neutrino models in cosmology, comparing them with the standard $\\Lambda$CDM model using observational $H(z)$ data, and finds no significant statistical improvement but notes some tension reduction.

Contribution

It provides observational constraints on MaVaN models, including non-flat variants, and compares their performance to $\\Lambda$CDM using multiple statistical criteria.

Findings

No statistically significant improvement of MaVaN over $\\Lambda$CDM.

MaVaN models reduce tension in $H_0$ measurements.

Deviations in expansion history are below $1\sigma$.

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 $\Lambda$CDM model, are derived from 32 $H(z)$ measurements using MCMC analysis. Comparison with the $\Lambda$CDM model using the criteria $\Delta\chi^2_{\rm min}$, $AICc$, and $BIC$ shows no statistically significant improvement for MaVaN models. Deviations in the expansion history remain well below $1\sigma$, indicating that the $H(z)$ data alone do not provide sufficient constraining power to distinguish MaVaN models from the $\Lambda$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 $\sim 2\sigma$ in the $\Lambda$CDM framework to $\sim 1.1\sigma$. The discrepancy with the SH0ES measurement of $H_0$ is also reduced to below $1\sigma$, primarily due to the large uncertainties of the $H(z)$ data.