A detailed understanding of leptogenesis

We discuss the necessary conditions for expaining the matter-Antimatter asymmetry in our universe and show how it can be realized by baryogenesis via leptogenesis. We study how the lepton number asymmery can occur in standard leptogenesis and introduce the process of conversion of the lepton number asymmetry into the baryon asymmetry through a sphaleron effective at finite temperature. The method to calculate the lepton number asymmetry generated from the decay of the heavy Majorana neutrino is presented. We derive the Boltzmann equation for the heavy Majorana neutrino, as well as the B - L to see how the lepton number asymmetry can survive without being completely washed out, and we discuss the physical implications of the contributions to the Boltzmann equation. By numerically solving the Boltzmann equation, we see how the lepton number asymmetry depends on the model parameters that reflect wash-out of the lepton number, and we find numerical results for the model parameters and the input variables, leading to the observed value of the bayron asymmetry in our universe.