The Early Universe represents an important environment to test the neutrino proprieties. Indeed Big Bang Nucleosynthesis (BBN), baryogenesis, Cosmic Microwave Background (CMB) radiation, Large Scale Structure formation
(LSS) could be essentially influenced by the presence of neutrinos, in particular by their number and their mass. In recent years a renewed attention has been devoted to low-mass sterile neutrinos (m ∼ 1 eV), after intriguing but controversial hints coming from precision cosmological measurements and laboratory oscillation experiments. Given the doubtful situation, is necessary to study the physical conditions under which the sterile production occurs and to investigate the consequences on the cosmological observables
