相关论文: Solving the discrepancy among the light elements a…
The primordial abundances of the light nuclides produced by Big Bang Nucleosynthesis (BBN) during the first 20 minutes in the evolution of the Universe are sensitive to the universal density of baryons and to the expansion rate of the early…
I present a model devoid of non-baryonic cold dark matter (CDM) which provides an acceptable fit to the WMAP data for the power spectrum of temperature fluctuations in the cosmic background radiation (CBR). An a priori prediction of such…
If there is a hidden photon -- i.e. a light abelian gauge boson in the hidden sector -- its kinetic mixing with the standard photon can produce a hidden cosmic microwave background (hCMB). For meV masses, resonant photon-hidden photon…
In the present work the primordial Big-Bang Nucleosynthesis (BBN) and weakly interacting massive particle (WIMP) dark matter are discussed in a certain class of modified gravitational theories, namely $f(R) \sim R^n$ gravity. The new…
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 $\Omega_b h^2 \approx 0.022 \sim 0.030$…
The Universe's initial conditions, in particular baryon and cold dark matter (CDM) isocurvature perturbations, are poorly constrained on sub-Mpc scales. In this paper, we develop a new formalism to compute the effect of small-scale baryon…
We present full sky microwave maps in five bands (23 to 94 GHz) from the WMAP first year sky survey. Calibration errors are <0.5% and the low systematic error level is well specified. The 2<l<900 anisotropy power spectrum is cosmic variance…
We update the Big Bang Nucleosynthesis calculations on the basis of the recent NACRE compilation. The average values of the calculated abundances of light nuclei do not differ significantly from that obtained using the previous Fowler's…
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…
A critical review is given of the current status of cosmological nucleosynthesis. In the framework of the standard model with 3 types of relativistic neutrinos, the baryon-to-photon ratio, \eta, corresponding to the inferred primordial…
Recent updates to the observational determinations of the primordial abundances of helium and deuterium are compared to the predictions of BBN to infer the universal ratio of baryons to photons (or, the present Universe baryon mass density…
The baryon-antibaryon asymmetry (excess of matter over antimatter in our Universe), indicated by observational data from the Cosmic Microwave Background anisotropies, predictions of primordial Nucleosynthesis, and the absence of intense…
The first year Wilkinson Microwave Anisotropy Probe (WMAP) set quantitative constraints on the amplitude of any primordial non-Gaussianity. We run a series of dark matter-only N-body simulations with the WMAP constraints to investigate the…
The theory of Big Bang nucleosynthesis, coupled with an estimate of the primordial deuterium abundance (D/H)_pr, offers insights into the baryon density of the Universe. Independently, the baryon density can be constrained during a…
Several anomalies appear to be present in the large-angle cosmic microwave background (CMB) anisotropy maps of WMAP. One of these is a lack of large-scale power. Because the data otherwise match standard models extremely well, it is natural…
A new upper limit on the amplitude of primordial magnetic field (PMF) is derived by a comparison between a calculation of elemental abundances in big bang nucleosynthesis (BBN) model and the latest observational constraints on the…
We evaluate abundance anomalies generated in patches of the universe where the baryon-to-photon ratio was locally enhanced by possibly many orders of magnitude in the range $\eta = 10^{-10} - 10^{-1}$. Our study is motivated by the possible…
A new observation of D in a primordial gas cloud, made using the high resolution spectrograph at the Keck telescope, indicates an abundance $ D/H =(1.9-2.5) \times 10^{-4}$ \cite{SCHR}. Since deuterium is destroyed by stars, and the…
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…
We combine detections of anisotropy in the Cosmic Microwave Background radiation with observations of inhomogeneity in the large-scale distribution of galaxies to test the predictions of models of cosmological structure formation. This…