Related papers: Mirror matter can alleviate the cosmological lithi…
Big-bang nucleosynthesis (BBN) theory, together with the precise WMAP cosmic baryon density, makes tight predictions for the abundances of the lightest elements. Deuterium and 4He measurements agree well with expectations, but 7Li…
We briefly review the concept of a parallel `mirror' world which has the same particle physics as the observable world and couples to the latter by gravity and perhaps other very weak forces. The nucleosynthesis bounds demand that the…
After a brief review of the cosmological lithium problem, we report a few recent attempts to find theoretical solutions by our group at Texas A&M University (Commerce & College Station). We will discuss our studies on the theoretical…
One of the still viable candidates for the dark matter is the so-called mirror matter. Its cosmological and astrophysical implications were widely studied in many aspects, pointing out the importance to go further with research and refine…
There can exist a parallel `mirror' world which has the same particle physics as the observable world and couples the latter only gravitationally. The nucleosynthesis bounds demand that the mirror sector should have a smaller temperature…
The discrepancy between the theoretical prediction of primordial lithium abundances and astronomical observations is called the Lithium Problem. We find that extra contributions from non-thermal hydrogen and helium during Big Bang…
According to the standard models of particle physics and cosmology, there should be a background of cosmic neutrinos in the present Universe, similar to the cosmic microwave photon background. The weakness of the weak interactions renders…
The measurement of the cosmic microwave background has strongly constrained the cosmological parameters of the Universe. When the measured density of baryons (ordinary matter) is combined with standard Big Bang nucleosynthesis calculations,…
Mirror world, a parallel hidden sector with microphysics identical to ordinary particle physics, can have several interesting phenomenological and astrophysical implications and mirror matter can be a natural candidate for dark matter in…
The abundance of primordial lithium is derived from the observed spectroscopy of metal-poor stars in the galactic halo. However, the observationally inferred abundance remains at about a factor of three below the abundance predicted by…
The $^7$Li abundance calculated in BBN with the baryon-to-photon ratio fixed from fits to the CMB power spectrum is inconsistent with the observed lithium abundances on the surface of metal-poor halo stars. Previous cosmological solutions…
The primordial lithium problem remains a persistent motivation for new-physics modifications of Big Bang nucleosynthesis, yet the precision of the observed deuterium abundance now places strong constraints on such attempts. This indicates…
We point out that the cosmological abundance of ${}^7$Li can be reduced down to observed values if during its formation Big Bang Nucleosynthesis is modified by the presence of light electrically neutral particles $X$ that have substantial…
We briefly review the concept of a parallel `mirror' world which has the same particle physics as the observable world and couples to the latter by gravity and perhaps other very weak forces. The nucleosynthesis bounds demand that the…
B and L violating interactions of ordinary particles with their twin particles from hypothetical mirror world can co-generate baryon asymmetries in both worlds in comparable amounts, $\Omega'_B/\Omega_B \sim 5$ or so. On the other hand, the…
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…
The existence of a shadow world (or mirror universe) with matter and forces identical to that of the visible world but interacting with the latter only via gravity can be motivated by superstring theories as well as by recent attempts to…
Combined with other CMB experiments, the WMAP survey provides an accurate estimate of the baryon density of the Universe. In the framework of the standard Big Bang Nucleosynthesis (BBN), such a baryon density leads to predictions for the…
To constrain the universe before recombination (380000 years after the Big Bang), we mostly rely on the measurements of the primordial abundances that indicate the first insight into the thermal history of the universe. The first production…
We briefly describe the cosmological lithium problems followed by a summary of our recent theoretical work on the magnitude of the effects of electron screening, the possible existence of dark matter parallel universes and the use of…