Baryogenesis via Leptogenesis: Spontaneous B and L Violation

Understand

In order to address the baryon asymmetry in the Universe one needs to understand the origin of baryon (B) and lepton (L) number violation.

• In this article, we discuss the mechanism of baryogenesis via leptogenesis to explain the matter-antimatter asymmetry in theories with spontaneous breaking of baryon and lepton number.
• In this context, a lepton asymmetry is generated through the out-of-equilibrium decays of right-handed neutrinos at the high-scale, while local baryon number must be broken below the multi-TeV scale to satisfy the cosmological bounds on the dark matter relic density.
• We demonstrate how the lepton asymmetry generated via leptogenesis can be converted in two different ways: a) in the theory predicting Majorana dark matter the lepton asymmetry is converted into a baryon asymmetry, and b) in the theory with Dirac dark matter the decays of right-handed neutrinos can generate lepton and dark matter asymmetries that are then partially converted into a baryon asymmetry.