Baryogenesis Through Mixing of Heavy Majorana Neutrinos

Abstract

A mechanism is presented, in which the mixing of right handed heavy Majorana neutrinos creates a $CP-$asymmetric universe. When these Majorana neutrinos subsequently decay more leptons than anti-leptons are produced. The lepton asymmetry created by this new mechanism can exceed by a few orders of magnitude any lepton asymmetry originating from direct decays. The asymmetry is finally converted into a baryon asymmetry during the electroweak phase transition.

Figures (4)

• Figure 1: $N_i$ and $N_i^c$ decaying into $l_{L \alpha}$ and $(l_{L \alpha})^c$
• Figure 2: One loop contributions to the mass matrix
• Figure 3: Comparison of the two $CP-$violating contributions to the lepton asymmetry in units of C, where $r = M_2^2/M_1^2$
• Figure 4: Lepton asymmetry in units of ${\cal C}$ generated for a small mass difference, where ${\rm P} = \sum_\alpha h^\ast_{\alpha 1} h_{\alpha 1}$ and ${\rm r} = M_2^2 / M_1^2$.