Related papers: Neutrino statistics and big bang nucleosynthesis
We assume that the Pauli exclusion principle is violated for neutrinos, and consequently, neutrinos obey the Bose-Einstein statistics. Cosmological and astrophysical consequences of this assumption are considered. Neutrinos may form…
We show how the $^4$He-abundance in the early Universe can be used to demonstrate that macroscopic samples of neutrinos in thermal equilibrium are indeed distributed according to Fermi-Dirac statistics.
We have performed new Big Bang Nucleosynthesis calculations which employ arbitrarily-specified, time-dependent neutrino and antineutrino distribution functions for each of up to four neutrino flavors. We self-consistently couple these…
According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders…
In this work we investigate the impact of two phenomenological Beyond the Standard Model (BSM) scenarios concerning the role of neutrinos in the early universe: non-standard neutrino interactions (NSI) and non-unitary three-neutrino mixing.…
We investigate the effect of the presence of non-pure fermionic neutrinos on the relativistic effective degrees of freedom in the early universe. The statistics of neutrinos is transformed continuously from Fermi-Dirac to Maxwell-Boltzmann…
We consider the phenomenological implications of the violation of the Pauli exclusion principle for neutrinos, focusing on cosmological observables such as the spectrum of Cosmic Microwave Background anisotropies, Baryon Acoustic…
We propose signals in the cosmic microwave background to probe the type and spectrum of neutrino masses. In theories that have spontaneous breaking of approximate lepton flavor symmetries at or below the weak scale, light pseudo-Goldstone…
We report the results on Big Bang Nucleosynthesis (BBN) based on an updated code, with accuracy of the order of 0.1% on He4 abundance, compared with the predictions of other recent similar analysis. We discuss the compatibility of the…
The effective number of neutrino species, $N_{\rm eff}$, serves as a key fitting parameter extensively employed in cosmological studies. In this work, we point out a fundamental inconsistency in the conventional treatment of $N_{\rm eff}$…
Observational manifestations of possible breaking of spin-statistics relation for neutrinos are considered. It is argued that bosonic neutrinos may form cosmological cold dark matter, improve agreement of BBN predictions with observations,…
It is usually assumed that relic neutrinos possess a Fermi-Dirac distribution, acquired during thermal equilibrium in the Early Universe. However, various mechanisms could introduce strong distortions in this distribution. We perform a…
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…
Cosmic Microwave Background (CMB) observations have been used extensively to constrain key properties of neutrinos, such as their mass. However, these inferences are typically dependent on assumptions about the cosmological model, and in…
We consider the cosmological effects of sterile neutrinos with the masses of $150- 450$ MeV. The decay of sterile neutrinos changes the thermal history of the Universe and affects the energy density of radiation at the recombination and the…
Ordinary-sterile neutrino oscillations can generate a significant lepton number asymmetry in the early Universe. We study this phenomenon in detail. We show that the dynamics of ordinary-sterile neutrino oscillations in the early Universe…
We consider the effect of inhomogeneous neutrino degeneracy on Big Bang nucleosynthesis for the case where the distribution of neutrino chemical potentials is given by a Gaussian. The chemical potential fluctuations are taken to be…
We consider the big bang nucleosynthesis (BBN) in the Brane world scenario, where all matter fields are confined on our 3-brane and the radion of the Brane evolves cosmologically. In the Einstein frame fundamental fermion masses vary and…
The role of neutrinos in big bang nucleosynthesis is reviewed. Neutrino oscillations in the early universe both in resonance and non-resonance case are briefly discussed. BBN and supernova limits on heavy sterile neutrinos with the mass in…
We re-examine neutrino oscillations in the early universe. Contrary to previous studies, we show that large neutrino asymmetries can arise due to oscillations between ordinary neutrinos and sterile neutrinos. This means that the Big Bang…