Throwing away antimatter via neutrino oscillations during the reheating era

Understand

The simplest possibility to explain the baryon asymmetry of the Universe is to assume that radiation is created asymmetrically between baryons and anti-baryons after the inflation.

• We propose a new mechanism of this kind where CP-violating flavor oscillations of left-handed leptons in the reheating era distribute the lepton asymmetries partially into the right-handed neutrinos while net asymmetry is not created.
• The asymmetry stored in the right-handed neutrinos is later washed out by the lepton number violating decays, and it ends up with the net lepton asymmetry in the Standard Model particles, which is converted into the baryon asymmetry by the sphaleron process.
• This scenario works for a range of masses of the right-handed neutrinos while no fine-tuning among the masses is required.