Related papers: Neutrinos and BBN (and the CMB)
A review of Big Bang Nucleosynthesis (BBN) is presented. Observations of deuterium and helium-4 are discussed. Some BBN restrictions on non-standard physics, especially on neutrino properties and time-variation of fundamental constants are…
We explore the effects of low-scale cosmological first-order phase transitions on Big Bang Nucleosynthesis (BBN) and Cosmic Microwave Background (CMB) anisotropy and distortion. We examine two scenarios: the distribution of the…
The existence of prolonged radiation domination prior to the Big Bang Nucleosynthesis (BBN), starting just after the inflationary epoch, is not yet established unanimously. If instead, the universe undergoes a non-standard cosmological…
Recent observation of the power spectrum of Cosmic Microwave Background (CMB) Radiation has exhibited that the flat cosmology is most likely. This suggests too large universal baryon-density parameter $\Omega_b h^2 \approx 0.022 \sim 0.030$…
We present calculations showing that upcoming Cosmic Microwave Background (CMB) experiments will have the power to improve on current constraints on neutrino masses and provide new limits on neutrino degeneracy parameters. The latter could…
The Cosmic Microwave Background (CMB) provides a precious window on fundamental physics at very high energy scales, possibly including quantum gravity, GUTs and supersymmetry. The CMB has already enabled defect-based rivals to inflation to…
Within the context of hot big-bang cosmology, a cosmic background of presently low energy neutrinos is predicted to exist in concert with the photons of the cosmic background radiation. The number density of the cosmological neutrinos is of…
We explore the effect of neutron lifetime and its uncertainty on standard big-bang nucleosynthesis (BBN). BBN describes the cosmic production of the light nuclides $^1{\rm H}$, ${\rm D}$, $^3{\rm H}$+$^3{\rm He}$, $^4{\rm He}$, and $^7{\rm…
An up to date review of Standard Big Bang Nucleosynthesis predictions vs the astrophysical estimates of light nuclei abundances is here presented. In particular the analysis reports the expected ranges for baryon fraction and effective…
In the primordial Big Bang nucleosynthesis (BBN), only the lightest nuclides (D, $^3$He, $^4$He, and $^7$Li) were synthesized in appreciable quantities, and these relics provide us a unique window on the early universe. Currently, BBN…
It is attractive to suppose for several astrophysical reasons that the universe has close to the critical density in light (~30 eV) neutrinos which decay radiatively with a lifetime of ~10^{23} sec. In such a cosmology the universe is…
Prediction of the primordial abundances of elements in the big-bang nucleosynthesis (BBN) is one of the three strong evidences for the big bang model. Precise knowledge of the baryon-to-photon ratio of the Universe from observations of the…
We update the Big Bang Nucleosynthesis (BBN) calculations on the basis of the recent NACRE compilation of reaction rates. We estimate the uncertainties related to the nuclear reaction rates on the abundances of D, 3He, 4He, 6Li, 7Li, 9Be,…
The discovery of cosmic microwave background (CMB) was a paradigm shift in the study and fundamental understanding of the early universe and also the Big Bang phenomenon. Cosmic microwave background is one of the richest and intriguing…
The primordial neutrino asymmetry leaves profound imprints on the evolution history of the universe, which can be constrained by cosmological observations, including Big Bang Nucleosynthesis (BBN), Cosmic Microwave Background (CMB), and…
We present an up-to-date review of Big Bang Nucleosynthesis (BBN). We discuss the main improvements which have been achieved in the past two decades on the overall theoretical framework, summarize the impact of new experimental results on…
Primordial or Big Bang nucleosynthesis (BBN) is one of the three strong evidences for the Big- Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation. In this study, we improve the standard BBN…
We present results from the analysis of cosmic microwave background (CMB), large scale structure (galaxy redshift survey) and X-ray galaxy cluster (baryon fraction and X-ray luminosity function) data, assuming a geometrically flat…
In conventional general relativity, the expansion rate H of a Robertson-Walker universe is related to the energy density by the Friedmann equation. Aside from the present day, the only epoch at which we can constrain the expansion history…
In the standard Big Bang cosmology the canonical value for the ratio of relic neutrinos to CMB photons is 9/11. Within the framework of the Standard Model of particle physics there are small corrections, in sum about 1%, due to slight…