We calculate the exact kinetic evolution of cosmic neutrinos during the epoch previous to Big Bang Nucleosynthesis, in the case when a large neutrino asymmetry exists. By solving numerically the Boltzmann kinetic equations for the neutrino distribution functions, we find the momentum-dependent corrections to the equilibrium spectrum of neutrinos and discuss their phenomenological implications. ...

Primordial nucleosynthesis provides a probe of the Universe during its early evolution. Given the progress exploring the constituents, structure, and recent evolution of the Universe, it is timely to review the status of Big Bang Nucleosynthesis (BBN) and to confront its predictions, and the constraints which emerge from them, with those derived from independent observations of the Universe at ...

It is usually assumed in stellar nucleosynthesis calculations that neutrons art completely thcrmalizcd. Hence, if the cross section of a neutron-induced reaction has a threshold, or it is suppressed by the Coulomb barrier in the exit channel, the reaction rate is quite low. However, the contribution front the decelerating fast neutrons has been neglected previously. We show that, though ihe fra...

In this paper it is investigated whether torsion, which arises naturally in most theories of quantum gravity, has observable implications for the Big Bang nucleosynthesis. Torsion can lead to spin flips amongst neutrinos thus turning them into sterile neutrinos. In the early Universe they can alter the helium abundance which is tightly constrained by observations. Here I calculate to what exten...

Constraints on the lifetime of the heavy sterile neutrino, that was proposed as a possible interpretation of the KARMEN anomaly, are derived from primordial nucleosynthesis and SN 1987A. Together with the recent experimental bounds on the νs lifetime, SN 1987A completely excludes this interpretation. Nucleosynthesis arguments permit a narrow window for the lifetime in the interval 0.1–0.2 sec. ...

For supersymmetric theories with gravitino dark matter, the maximal reheating temperature consistent with big bang nucleosynthesis bounds arises when the physical gaugino masses are degenerate. We consider the cases of a stau or sneutrino next-tolightest superpartner, which have relatively less constraint from big bang nucleosynthesis. The resulting parameter space is consistent with leptogenes...

We investigate in detail the parameter space of active-sterile neutrino oscillations that amplifies neutrino chemical potentials at the epoch of Big Bang Nucleosynthesis. We calculate the magnitude of the amplification and show evidences of chaos in the amplification process. We also discuss the implications of the neutrino chemical potential amplification in the Big Bang Nucleosynthesis. It is...

Two recent issues realted to nucleosynthesis in early proton-rich neutrino winds are investigated. In the first part we investigate the effect of nuclear physics uncertainties on the synthesis of 92Mo and 94Mo. Based on recent experimental results, we find that the proton rich winds of the model investigated here can not be the only source of the solar abundance of 92Mo and 94Mo. In the second ...

We study the nucleosynthesis of the light elements Li and B and the rprocess elements in Type II supernovae from the point of view of supernova neutrinos and Galactic chemical evolution. We investigate the influence of the luminosity and average energy (temperature) of supernova neutrinos on these two nucleosynthesis processes. Common models of the neutrino luminosity, which is parameterized by...

The chemical evolution of galaxies is governed by the yields from stars, and here we focus on important contributions asymptotic giant branch (AGB) stars. AGB nucleosynthesis is, however, still riddled with complexities. Observations post-asymptotic (post-AGB) stars serve as exquisite tools to quantify understand nucleosynthesis. In this contribution, review invaluable constraints provided post...