Related papers: Updated BBN bounds on the cosmological lepton asym…
While the baryon asymmetry of the Universe is nowadays well measured by cosmological observations, the bounds on the lepton asymmetry in the form of neutrinos are still significantly weaker. We place limits on the relic neutrino asymmetries…
The cosmic energy density in the form of radiation before and during Big Bang Nucleosynthesis (BBN) is typically parameterized in terms of the effective number of neutrinos N_eff. This quantity, in case of no extra degrees of freedom,…
At temperatures below the QCD phase transition, any substantial lepton number in the Universe can only be present within the neutrino sector. In this work, we systematically explore the impact of a non-vanishing lepton number on Big Bang…
Recent observations of the cosmic microwave background (CMB) at smallest angular scales and updated abundances of primordial elements, indicate an increase of the energy density and the helium-4 abundance with respect to standard big bang…
Recently it is reported that there is the discrepancy between big bang nucleosynthesis theory and observations (BBN crisis). We show that BBN predictions agree with the primordial abundances of light elements, He4, D, He3 and Li7 inferred…
We numerically solve the evolution equations of neutrino three-flavor density matrices, and show that, even if neutrino oscillations mix neutrino flavors, large lepton number asymmetries are still allowed in certain limits by Big Bang…
The recent discovery of nonzero $\theta_{13}$ (equal to Cabbibo angle $\theta_C$ up to a factor of $\sqrt{2}$), the masses of supersymmetric particles $\gapp$ TeV from LHC data, and the sum of three active neutrino masses $\sum_i…
We study three-flavor neutrino oscillations in the early universe in the presence of neutrino chemical potentials. We take into account all effects from the background medium, i.e. collisional damping, the refractive effects from charged…
The question "how small is the lepton mixing angle \theta_{13}?" had a convincing answer in a surprisingly short time, \theta_{13} \simeq 9^{\circ}, a large value comparable to the Chooz limit. It defines a new epoch in the program of…
Primordial Big-Bang Nucleosynthesis (BBN) tightly constrains the existence of any additional relativistic degrees of freedom at that epoch. However a large asymmetry in electron neutrino number shifts the chemical equilibrium between the…
We assess the effects on Big Bang Nucleosynthesis (BBN) of lepton number generation in the early universe resulting from the two-doublet four-neutrino mass/mixing scheme. It has been argued that this neutrino mass/mixing arrangement gives…
The data on atmospheric neutrinos can be explained assuming the existence of oscillations between muon neutrinos and light sterile neutrinos with mixing close to maximal, and Delta_m^2 approximately equal to 3 E-3 (eV^2). This…
We study the impact of minimal non-supersymmetric models of resonant leptogenesis on charged lepton flavour violation and the neutrino mixing angle theta(13). Possible low-scale flavour realisations of resonant tau-, mu- and e-leptogenesis…
In this article, we study the implications of the coupling between Axion-Like-Particles (ALPs) and Leptons to cosmology, in particular, the Big Bang Nucleosynthesis (BBN). We show that the BBN, through the constraint on the effective number…
Oscillations between ordinary and sterile neutrinos can generate large neutrino asymmetries in the early universe. These asymmetries can significantly affect big bang nucleosynthesis (BBN) through modification of nuclear reaction rates. We…
We present a model for leptonic mixing and the lepton masses based on flavor symmetries and higher-dimensional mass operators. The model predicts bilarge leptonic mixing (i.e., the mixing angles theta_{12} and theta_{23} are large and the…
We place constraints on the number of relativistic degrees of freedom and on the baryon asymmetry at the epoch of Big Bang Nucleosynthesis (BBN) and at recombination, using cosmic background radiation (CBR) data from the Wilkinson Microwave…
Primordial neutrino-antineutrino asymmetries can be constrained through big-bang nucleosynthesis (BBN) relic abundances and cosmic microwave background (CMB) anisotropies, both observables being sensitive to neutrino properties. The latter…
By using most of the present CMB and LSS measurements and the BBN constraints on the primordial helium abundance, Y_p, we set bounds on the radiation content of the Universe and neutrino properties. We consider lepton asymmetric…
Nucleosynthesis restrictions on mixing of active neutrinos with possible sterile ones are obtained with the account of experimentally determined mixing between all active neutrinos. The earlier derived bounds, valid in the absence of…