The electron-neutrino system, ch. 3

Relativistic kinetic gas theory is applied to a mixture of electrons and electronic neutrinos. The phenomena of diffusion are especially studied in this system, assuming properties comparable to those of the universe in the lepton era as assumed in the hot big bang theory: a hot (Tapproximately 1012K), dense (n = 1038) mixture, colliding elastically. An expression for the diffusion coefficient is derived and numerical values are computed as a function of the reduced temperature z-1 = kT/mc2, assuming equal number densities