Speaker
Description
We investigate the possibility of viable leptogenesis in an appealing $\Delta(27)$ model with a universal texture zero. The model accommodates the mass spectrum, mixing and CP phases for both quarks and leptons and allows for grand unification. Flavoured Boltzmann equations for the lepton asymmetries are solved numerically, taking into account both $N_1$ and $N_2$ right-handed neutrino decays. We show that leptogenesis is separately possible in either the $N_1$ and $N_2$ dominated scenarios, with the asymmetry in the electron flavour protected from the $N_1$-washout by the texture zero. The two viable regions of the parameter space are $M_1\in[10^9,10^{12}]$, with $M_1/M_2\in[0.002,0.1]$, and $M_1\in[10^9,10^{10}]$, with $M_1/M_2<0.002$ and $M_2$ relatively close to $M_3$, which however is not a natural expectation of the $\Delta(27)$ model. We conclude that the $N_1$-dominated scenario is successful and the most natural option for the model.
