Impact of the damping tail on neutrino mass constraints

TL;DR

This paper derives updated cosmological limits on neutrino masses and effective number of neutrino species using high-multipole CMB data from ACT and SPT-3G, combined with other cosmological observations, considering various cosmological models.

Contribution

It provides the first comprehensive analysis of neutrino mass constraints incorporating ACT and SPT-3G polarization data with multiple cosmological models, improving robustness of bounds.

Findings

Neutrino mass sum constrained to <0.139 eV at 95% CL.

Effective neutrino number N_eff estimated as 2.82±0.25.

Results are competitive with Planck-based analyses.

Abstract

Model-independent mass limits assess the robustness of current cosmological measurements of the neutrino mass scale. Consistency between high-multipole and low-multiple Cosmic Microwave Background observations measuring such scale further valuate the constraining power of present data. We derive here up-to-date limits on neutrino masses and abundances exploiting either the Data Release 4 of the Atacama Cosmology Telescope (ACT) or the South Pole Telescope polarization measurements from SPT-3G, envisaging different non-minimal background cosmologies and marginalizing over them. By combining these high-$\ell$ observations with Supernova Ia, Baryon Acoustic Oscillations (BAO), Redshift Space Distortions (RSD) and a prior on the reionization optical depth from WMAP data, we find that the marginalized bounds are competitive with those from Planck analyses. We obtain $\sum m_\nu <0.139$ eV and $N_{\textrm{eff}}= 2.82\pm 0.25$ in a dark energy quintessence scenario, both at $95\%$ CL. These limits translate into $\sum m_\nu <0.20$ eV and $N_{\textrm{eff}}= 2.79^{+0.30}_{-0.28}$ after marginalizing over a plethora of well-motivated fiducial models. Our findings reassess both the strength and the reliability of cosmological neutrino mass constraints.