Related papers: Primordial Nucleosynthesis and Finite Temperature …
We have calculated the small effect of finite nucleon mass on the weak-interaction rates that interconvert protons and neutrons in the early Universe. We have modified the standard code for primordial nucleosynthesis to include these…
Primordial or big bang nucleosynthesis (BBN) is one of the three historical strong evidences for the big bang model. Standard BBN is now a parameter free theory, since the baryonic density of the Universe has been deduced with an…
Recent determinations of the deuterium abundance, $^2$H/H, in high redshift Lyman limit hydrogen clouds challenge the usual picture of primordial nucleosynthesis based on \lq\lq concordance\rq\rq\ of the calculated light element ($^2$H,…
We study the vacuum polarization tensor of QED (quantum electrodynamics) at high temperatures up to the two loop levels and its effect on the electromagnetic properties of a medium. One loop corrections to QED coupling vanish at low…
In the primordial Universe, neutrino decoupling occurs only slightly before electron-positron annihilations, leading to an increased neutrino energy density with order $10^{-2}$ spectral distortions compared to the standard instantaneous…
As electromagnetic showers may alter the abundance of Helium, Lithium, and Deuterium, we can place severe constraints on the lifetime and amount of electromagnetic energy injected by long-lived particles. Considering up-to-date measurements…
We study the impact of an early dark energy component (EDE) present during big bang nucleosynthesis (BBN) on the elemental abundances of deuterium D/H, and helium $Y_p$, as well as the effective relativistic degrees of freedom $N_{\rm…
Limits can be placed on nonstandard neutrino physics when big bang nucleosynthesis (BBN) calculations employing standard neutrino physics agree with the observationally inferred primordial abundances of deuterium (D), $^3$He, $^4$He, and…
As the early universe expands and cools the rates of the weak interactions that keep neutrinos in thermal equilibrium with the matter and the related rates of the reactions that inter-convert neutrons and protons decrease. Eventually, these…
We analyze a new mechanism for the cosmological QCD first-order phase transition: inhomogeneous nucleation. The primordial temperature fluctuations are larger than the tiny temperature interval, in which bubbles would form in the standard…
We study the effects of dark-matter annihilation during the epoch of big-bang nucleosynthesis on the primordial abundances of light elements. We improve the calculation of the light-element abundances by taking into account the effects of…
We consider the implications of the modified dispersion relations, due to the noncommutativity of the spacetime, for a photon gas filling the early Universe in the framework of the Big Bang Nucleosynthesis (BBN) processes, during the period…
A massive long-lived tau neutrino in the MeV regime modifies the primordial light-element abundances predicted by big-bang nucleosynthesis (BBN) calculations. This effect has been used to derive limits on the tau neutrino mass. Because…
The light elements up to 7Li were produced by the Standard Big Bang nucleosynthesis (SBBN) in the early universe assuming standard conditions. All observed primordial abundances of these light elements match very well the predicted ones by…
We have reexamined the electromagnetic corrections to the weak interaction rates for the transformation of neutrons to protons, and protons to neutrons, in the early universe, before freeze-out. We derive compact expressions for these rates…
Primordial or Big Bang nucleosynthesis (BBN) is one of the three historical strong evidences for the Big-Bang model together with the expansion of the Universe and the Cosmic Microwave Background radiation (CMB). The recent results by the…
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…
Recently we presented a simple method for determining the correlated uncertainties of the light element abundances expected from big bang nucleosynthesis, which avoids the need for lengthy Monte Carlo simulations. We now extend this…
Light, weakly-coupled dark sectors may be naturally decoupled in the early universe and enter equilibrium with the Standard Model bath during the epoch of primordial nucleosynthesis. The equilibration and eventual decoupling of dark sector…
We use the semi-analytic method of \citet{Esma91} to calculate the abundances of Helium and Deuterium produced during Big Bang nucleosynthesis assuming the fine structure constant and the Higgs vacuum expectation value may vary in time. We…