Relaxing cosmological constraints on current neutrino masses: Parameter Estimation

cover
24 May 2024

This paper is available on arxiv under CC 4.0 license.

Authors:

(1) Vitor da Fonseca, Instituto de Astrof┬┤─▒sica e Ci╦ćencias do Espa┬Şco, Faculdade de Ci╦ćencias da Universidade de Lisboa;

(2) Tiago Barreiro, Instituto de Astrof┬┤─▒sica e Ci╦ćencias do Espa┬Şco, Faculdade de Ci╦ćencias da Universidade de Lisboa and 2ECEO, Universidade Lus┬┤ofona;

(3) Nelson J. Nunes, Instituto de Astrof┬┤─▒sica e Ci╦ćencias do Espa┬Şco, Faculdade de Ci╦ćencias da Universidade de Lisboa.

IV. PARAMETER ESTIMATION

A. Methodology

The likelihoods are minimized using the Monte Carlo code of the MontePython parameter estimation package [62, 63], which samples the parameter space and the posterior probability distributions using a Metropolis-Hastings algorithm with the flat priors specified in Table I. The size of the prior intervals is sufficient for the corresponding posteriors to fall exponentially within them, except for the parameter ╬▓ as we will discuss later.

TABLE I: Flat priors for the sampled model and cosmological parameters.

B. Main results

The results of the likelihood analysis are summarized in Table II, which lists the constraints on the cosmological parameters obtained with the Plk18+BAO data set for both the uncoupled (╬▓ = 0) scalar field model and the coupled MaVaN model. They lead to several remarkable conclusions.

FIG. 7: Constraints obtained with the Plk18+BAO data set on the additional parameters. Probability distributions and 2D marginalised contours (68% and 95% CL).

TABLE III: Constraints on present neutrino mass in eV and on the dark energy parameter ╬╗, for different coupling values ╬▓.