Relic neutrinos play an important role in the evolution of the Universe, having a remarkable impact on the cosmological observables. Notably, Big Bang Nucleosynthesis (BBN), Cosmic Microwave Background (CMB) and the Structure Formation (LSS) data represent powerful probes for the neutrino properties. In this talk we show how these cosmological data can be used to bound the absolute scale of neutrino masses and the effective number of neutrino species (N_eff). We also discuss the cosmological impact of sterile neutrinos (with keV and eV masses), that would act as a portal towards new physics scenarios. In particular, keV sterile neutrinos would play the role of DM in the Universe, while eV sterile neutrinos, suggested by laboratory anomalies, could modify the standard framework requiring large primordial neutrino asymmetries or secret neutrino self-interactions to accommodate these particles with cosmological observations.
Friday, January 23, 2015 - 13:15
Building 44 (Shackleton) - Lecture Theatre B
Neutrinos in cosmology: current bounds and new physics scenarios