Cosmological Nucleosynthesis and Active-Sterile Neutrino Oscillations with Small Mass Differences: The Nonresonant Case

D. P. Kirilova, M. V. Chizhov

We study the nonresonant oscillations between left-handed electron neutrinos nu_e and nonthermalized sterile neutrinos nu_s in the early Universe plasma. The case when nu_s do not…