Possible Impact of non-Gaussianities on cosmological constraints in neutrino physics

TL;DR

This paper investigates how non-Gaussian features in the CMB, modeled by the Super-ΛCDM extension, can affect constraints on neutrino masses, potentially relaxing current limits and introducing biases.

Contribution

It demonstrates that the Super-ΛCDM model's additional parameters can significantly alter neutrino mass constraints, highlighting the importance of considering non-Gaussianities in cosmological analyses.

Findings

Super-ΛCDM parameter $A_0$ deviates from zero at over 95% confidence.

Neutrino mass constraints can be relaxed by over a factor of two.

Ignoring non-Gaussianities may lead to overly stringent neutrino mass limits.

Abstract

The search for non-Gaussian signatures in the Cosmic Microwave Background (CMB) is crucial for understanding the physics of the early Universe. Given the possibility of non-Gaussian fluctuations in the CMB, a recent revision to the standard $\Lambda$-Cold Dark Matter ($\Lambda$CDM) model has been proposed, dubbed "Super-$\Lambda$CDM". This model introduces additional free parameters to account for the potential effects of a trispectrum in the primordial fluctuations. In this study, we explore the impact of the Super-$\Lambda$CDM model on current constraints on neutrino physics. In agreement with previous research, our analysis reveals that for most of the datasets, the Super-$\Lambda$CDM parameter $A_0$ significantly deviates from zero at over a $95\%$ confidence level. We then demonstrate that this signal might influence current constraints in the neutrino sector. Specifically, we find that the current constraints on neutrino masses may be relaxed by over a factor of two within the Super-$\Lambda$CDM framework, thanks to the correlation present with $A_0$. Consequently, locking $A_0=0$ might introduce a bias, leading to overly stringent constraints on the total neutrino mass.