Leptogenesis in Δ(27) with a universal texture zero

Abstract

Abstract We investigate the possibility of viable leptogenesis in an appealing Δ(27) model with a universal texture zero in the (1,1) entry. 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. The N 1-dominated scenario is successful and the most natural option for the model, with M 1 ∈ [109 , 1012] GeV, and M 1 /M 2 ∈ [0.002, 0.1], which constrains the parameter space of the underlying model and yields lower bounds on the respective Yukawa couplings. Viable leptogenesis is also possible in the N 2-dominated scenario, with the asymmetry in the electron flavour protected from N 1 washout by the texture zero. However, this occurs in a region of parameter space which has a stronger mass hierarchy M 1 /M 2 < 0.002, and M 2 relatively close to M 3, which is not a natural expectation of the Δ(27) model.