“Massive Neutrinos and Cosmology”

Abstract

Neutrinos play a fundamental role in both particle physics and cosmology, providing an important bridge between the physics of the very small and the largest scales of the Universe. While neutrino oscillation experiments have firmly established that neutrinos are massive, their absolute mass scale and the mechanism responsible for their mass generation remain unknown. In cosmology, neutrinos leave distinctive imprints on the evolution of the Universe, affecting key observables such as the Cosmic Microwave Background and the large-scale structure. In this thesis, we investigate the role of neutrinos in the evolution of the Universe and use cosmological observations to constrain their properties within a variety of theoretical frameworks. We analyze the impact of neutrino masses on structure formation and explore their correlation with extensions of the standard cosmological model, including inflationary scenarios and dynamical dark energy models. Our results show that cosmological data provide stringent bounds on the sum of neutrino masses, offering important and complementary information to laboratory experiments. In particular, we demonstrate how different cosmological assumptions, such as the nature of dark energy or the inclusion of curvature, can affect these constraints. We also present forecasts for future galaxy surveys, highlighting their potential to further improve the sensitivity to the absolute neutrino mass.