Related papers: Neutrino Dark Matter
We analyze a scenario in which the lightest heavy neutrino $N_1$ is a dark matter candidate and the second- heaviest neutrino $N_2$ decays producing a lepton number. If $N_1$ were in thermal equilibrium, its energy density today would be…
Neutrinos are amongst the most abundant particles in the universe. The fact that they are massive particles proves that the Standard Model is an incomplete theory and needs to be extended. This thesis focuses on the study of neutrino…
In these lectures I highlight some key features of massive neutrinos in the context of cosmology. I first review the thermal history and the free-streaming kinematics of the uniform cosmic background neutrinos. I then describe how…
Two of the most important and pressing questions in cosmology and particle physics are: (1) What is the nature of cold dark matter? and (2) Will near-future experiments on neutrinoless double beta decay be able to ascertain that the…
We propose a new explanation of the intriguing LSND evidence for electron antineutrino appearance in terms of heavy (mostly sterile) neutrino decay via a coupling with a light scalar and light (mostly active) neutrinos. We perform a fit to…
A new and radical scenario of the simple 2006 model of radiative neutrino mass is proposed, where there is no seesaw mechanism, i.e. neutrino masses are not inversely proportional to some large mass scale, contrary to the prevalent…
In several recent papers it was claimed that SN 1987A data supports the existence of 4.0 eV and 21.4 eV active neutrino mass eigenstates, and it was shown that such large masses could be made consistent with existing constraints including…
The recent observation of neutrino oscillations with atmospheric and solar neutrinos, implying that neutrinos are not massless, is a discovery of paramount importance for particle physics and particle astrophysics. This invited lecture…
In the Supersymmetric extension of the Standard Model with minimal particle content the three neutrinos can have non trivial masses and mixings, generated at 1 loop due to renormalizable lepton number violating interactions. We show that…
An alternative to the famous see-saw mechanism is proposed to explain the smallness of the neutrino masses (if present). This model involves a fourth family which mixes very little with the other three. It contains one heavy neutrino (mN >…
There is a renewed interest in constraining the sum of the masses of the three neutrino flavours by using cosmological measurements. Solar, atmospheric, and reactor neutrino experiments have confirmed neutrino oscillations, implying that…
We discuss a model in which three active and one sterile neutrino account for the solar, the atmospheric and the LSND neutrino anomalies. It is shown that if $N_\nu<4$ then these and other experiments and big bang nucleosynthesis constrain…
Recent indications from both particle physics and cosmology suggest the existence of more than three neutrino species. In cosmological analyses the effects of neutrino mass and number of species can in principle be disentangled for fixed…
Sterile neutrinos may be one of the best Warm Dark Matter candidates we have today. Both lower and upper bounds on the mass of the sterile neutrino come from astronomical observations. We show that the proper inclusion of the neutrino…
If light sterile neutrinos are needed to understand the neutrino puzzles, as is currently indicated, a major theoretical challenge is to understand why its mass is so small. It is a more serious problem than understanding the small mass of…
We investigate an extension of the Minimal Standard Model by right-handed neutrinos (the $\nu$MSM) to incorporate neutrino masses consistent with oscillation experiments. Within this theory, the only candidates for dark matter particles are…
The question of neutrino mass is one of the major riddles in particle physics. Recently, strong evidence that neutrinos have nonzero masses has been found. While tiny, these masses could be large enough to contribute significantly to the…
Despite the astonishing success of standard $\Lambda$CDM cosmology, there is mounting evidence for a tension with observations at small and intermediate scales. We introduce a simple model where both cold dark matter (DM) and sterile…
The evidence for the existence of dark matter in the universe is reviewed. A general picture emerges, where both baryonic and non-baryonic dark matter is needed to explain current observations. In particular, a wealth of observational…
In this review we discuss how the models of neutrino masses can accommodate solutions to the problem of matter-antimatter asymmetry in the universe, dark energy or cosmological constant problem and dark matter candidates. The…