Related papers: Primordial Nucleosynthesis and Finite Temperature …
We point out that the existence of metastable, tau > 10^3 s, negatively charged electroweak-scale particles (X^-) alters the predictions for lithium and other primordial elemental abundances for A>4 via the formation of bound states with…
We consider Big Bang Nucleosynthesis (BBN) with long lived charged massive particles. Before decaying, the long lived charged particle recombines with a light element to form a bound state like a hydrogen atom. This effect modifies the…
To elucidate the significance of the effect of systematic uncertainties in light element abundance estimates on cosmological bounds derivable from Big Bang Nucleosynthesis (BBN) we present tables giving bounds on $\Omega_{baryon}$ and…
Tests of big bang nucleosynthesis and early universe cosmology require precision measurements for helium abundance determinations. However, efforts to determine the primordial helium abundance via observations of metal poor H II regions…
The theory of QED corrections to hyperfine structure in light hydrogenic atoms and ions has recently advanced to the point that the uncertainty of these corrections is much smaller than 1 part per million (ppm), while the experiments are…
Late-decaying particles naturally arise in many extensions of the Standard Model, directly impacting key cosmological processes in the early universe, such as Big Bang Nucleosynthesis (BBN). BBN studies often consider electromagnetic energy…
We extend previous studies of big bang nucleosynthesis, with the assumption that ordinary matter and dark matter sectors are entangled through the number of degrees of freedom entering the Friedmann equations. This conjecture allows us to…
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…
Using a real-time formalism of equilibrium and nonequilibrium quantum-field theory, we derive the reaction-rate formula for neutrino-conversion ($\nu \to \nu'$) process and $\nu \bar{\nu}'$ annihilation process, which take place in a hot…
We discuss the effects of a possible time variation of the Newton constant $G_{\rm N}$ on light elements production in Big Bang Nucleosyntesis (BBN). We provide analytical estimates for the dependence of primordial abundances on the value…
The primordial abundances of deuterium, helium-3, helium-4, and lithium-7 probe the baryon density of the Universe only a few minutes after the Big Bang. Of these relics from the early Universe, deuterium is the baryometer of choice. After…
In this paper we consider the effects on big bang nucleosynthesis (BBN) of the hadronic decay of a long-lived massive particle. If high-energy hadrons are emitted near the BBN epoch ($t \sim 10^{-2}$ -- $10^2 \sec$), they extraordinarily…
The apparent discrepancy between abundances of light nuclides predicted by the standard Big-Bang and observational data is explained, by assuming the presence of metastable H dibaryons at the nucleosynthesis era. These dibaryons could be…
We reanalyze the cosmological constraints on the existence of a net universal lepton asymmetry and neutrino degeneracy. We show that neutrinos can begin to decouple at higher temperatures than previous estimates due to several corrections…
Big bang nucleosynthesis provides the earliest probe of standard model physics, at a time when the universe was less than a thousand seconds old. It determines the abundances of the lightest nuclides, which give rise to the subsequent…
The generation of a kination-dominated phase by a quintessential exponential model is investigated and the parameters of the model are restricted so that a number of observational constraints (originating from nucleosynthesis, the present…
The determination of the primeval deuterium abundance has opened a precision era in big-bang nucleosynthesis (BBN), making accurate predictions more important than ever before. We present in analytic form new, more precise predictions for…
We put bounds on the variation of the value of the fine structure constant $\alpha$, at the time of Big Bang nucleosynthesis. We study carefully all light elements up to $^7$Li. We correct a previous upper limit on $|\Delta \alpha /…
WThe current status of big bang nucleosynthesis is reviewed with an emphasis on the comparison between the observational determination of the light element abundances of \D, \he3, \he4 and \li7 and the predictions from theory. In…
The effects of introducing a small amount of non-thermal distribution (NTD) of elements in big bang nucleosynthesis (BBN) are studied by allowing a fraction of the NTD to be time-dependent so that it contributes only during a certain period…