Related papers: Cosmic Deuterium and Baryon Density
(Abridged) Estimates of the interstellar deuterium abundance span a wide range of values. Here we study the evolution of deuterium in the framework of successful models for the chemical evolution of the Milky Way able to reproduce the…
For a brief time in its early evolution the Universe was a cosmic nuclear reactor. The expansion and cooling of the Universe limited this epoch to the first few minutes, allowing time for the synthesis in astrophysically interesting…
We revisit the state of the light element abundances from big bang nucleosynthesis in early 2024 with particular focus on the derived baryon abundance. We find that the largest differences between the final baryon abundances are typically…
For dark matter (DM) particles with masses in the 0.6 - 6 m_p range, we set stringent constraints on the interaction cross-sections for scattering with ordinary baryonic matter. These constraints follow from the recognition that such…
We derive constraints on cosmological parameters using the power spectrum of galaxy clustering measured from the final two-degree field galaxy redshift survey (2dFGRS) and a compilation of measurements of the temperature power spectrum and…
The accurate evaluation of the nuclear reaction rates and corresponding uncertainties is an essential requisite for a precise determination of light nuclide primordial abundances. The recent measurement of the D(p,gamma)3He radiative…
The recent detection of microlensing of stars of LMC by compact objects in the halo of our galaxy suggests that our galaxy is surrounded by a non-luminous halo made of compact objects with mass of about $(0.03-0.5) \msun$. The rate of…
We revisit the process of gravitational sedimentation of helium and heavy elements in the intra-cluster medium. We find that helium applies an inward drag force on heavy elements, boosting their sedimentation speed to nearly half its own.…
Recent Cosmological measurements indicate that baryons comprise about four percent of the total mass-energy density of the Universe, which is in accord with the predictions arising from studies of the production of the lightest elements. It…
Primordial nucleosynthesis is one of the three historical evidences for the big bang model, together with the expansion of the universe and the cosmic microwave background. Now that the number of neutrino families and the baryonic densities…
Molecular gas, modest in mass yet pivotal within the cosmic inventory, regulates baryon cycling as the immediate fuel for star formation. Across most of cosmic history, its reservoir has remained elusive, with only the tip of the iceberg…
In high energy collisions nuclei are practically transparent to each other but produce very hot, nearly baryon-free, matter in the central rapidity region. Where do the baryons go? We calculate the energy loss of the nuclei using the color…
We include new data in an updated analysis of helium in low metallicity extragalactic HII regions with the goal of deriving the primordial abundance of He4 (Y_P). We show that the new observations of Izotov et al (ITL) are consistent with…
The properties of dense QCD matter are delineated through the construction of equations of state which should be consistent with the low and high density limits of QCD, nuclear laboratory experiments, and the neutron star observations.…
Big bang nucleosynthesis (BBN) and the cosmic microwave background (CMB) are two major pillars of cosmology. Standard BBN accurately predicts the primordial light element abundances ($^4$He, D, $^3$He and $^7$Li), depending on one…
Recent spacecraft observations exploring solar system properties impact standard paradigms of the formation of stars, planets and comets. We stress the unexpected cloud of microscopic dust resulting from the DEEP IMPACT mission, and the…
The cosmic star formation histories are evaluated for different minimum masses of the initial halo structures, with allowance for realistic gas outflows. With a minimum halo mass of 10^{7} - 10^{8} M_odot and a moderate outflow efficiency,…
Recent measurements of deuterium abundances from QSO absorption spectra show two conflicting numbers, which differ by an order of magnitude. Allowing the neutrino degeneracy together with gravitational constant variation at the epoch of…
We have used recent observations of helium-4, nitrogen and oxygen from some four dozen, low metallicity, extra-galactic HII regions to define mean $N$ versus $O$, $^4He$ versus $N$ and $^4He$ versus $O$ relations which are extrapolated to…
The recent Boomerang and MAXIMA data on the cosmic microwave background suggest a large value for the baryonic matter density of the universe, omega_b = 0.03. This density is larger than allowed by standard big bang nucleosynthesis theory…