Leptogenesis in $E_6 \times U(1)_A$ SUSY GUT model

Understand

We study the thermal leptogenesis in the $E_6\times U(1)_A$ SUSY GUT model in which realistic masses and mixings of quarks and leptons can be realized.

• We show that the sufficient baryon number can be produced by the leptogenesis in the model, in which the mass parameter of the lightest right-handed neutrino is predicted to be smaller than $10^8$ GeV.
• The essential point is that the mass of the lightest right-handed neutrino can be enhanced in the model because it has a lot of mass terms whose mass parameters are predicted to be the same order of magnitude which is smaller than $10^8$ GeV.
• We show that O(10) enhancement for the lightest right-handed neutrino mass is sufficient for the observed baryon asymmetry.