Leptogenesis and fermion mass fit in a renormalizable SO(10) model

A non-supersymmetric renormalizable SO(10) model is investigated for its viability in explaining the observed fermion masses and mixing parameters along with the baryon asymmetry produced via thermal leptogenesis. The Yukawa sector of the model consists of complex 10(H) and (126) over bar (H) scalars with a Peccei-Quinn like symmetry and it leads to strong correlations among the Yukawa couplings of all the standard model fermions including the couplings and masses of the right-handed (RH) neutrinos. The latter implies the necessity to include the second lightest RH neutrino and flavor effects for the precision computation of leptogenesis. We use the most general density matrix equations to calculate the temperature evolution of flavoured leptonic asymmetry. A simplified analytical solution of these equations, applicable to the RH neutrino spectrum predicted in the model, is also obtained which allows one to fit the observed baryon to photon ratio along with the other fermion mass observables in a numerically efficient way. The analytical and numerical solutions are found to be in agreement within a factor of O(1). We find that the successful leptogenesis in this model does not prefer any particular value for leptonic Dirac and Majorana CP phases and the entire range of values of these observables is found to be consistent. The model specifically predicts (a) the lightest neutrino mass m(nu 1) between 2-8 meV, (b) the effective mass of neutrinoless double beta decay m(beta beta) between 4-10 meV, and (c) a particular correlation between the Dirac and one of the Majorana CP phases.

Automated summary

The viability of a non-supersymmetric renormalizable SO(10) model in explaining observed fermion masses, mixing parameters, and baryon asymmetry through thermal leptogenesis is investigated. The Yukawa sector of the model shows strong correlations among the Yukawa couplings of standard model fermions and the necessity to consider the second lightest RH neutrino and flavor effects for precise computation of leptogenesis. Analytical and numerical solutions in the model are found to be consistent, predicting specific values for neutrino masses and double beta decay effective mass.