Nonequilibrium neutrino spectra in the early universe

Abstract

Abstract In this talk we discuss the non-equilibrium corrections to the neutrino spectrum in the early Universe. We present the results of a numerical simulation of the set of kinetic equations for the neutrino distribution functions. The final values of the distortion of the energy densities are approximately 0.9∼ for ve and 0.4∼ for vμ and v r. This effect leads to an increase in the primordial 4He abundance of 1.4.10−-4.