Flavour symmetries in a renormalizable SO(10) model

In the context of a renormalizable supersymmetric SO(10) Grand Unified Theory, we consider the fermion mass matrices generated by the Yukawa couplings to a 10⊕120⊕126‾ representation of scalars. We perform a complete investigation of the possibilities of imposing flavour symmetries in this scenario; the purpose is to reduce the number of Yukawa coupling constants in order to identify potentially predictive models. We have found that there are only 14 inequivalent cases of Yukawa coupling matrices, out of which 13 cases are generated by Zn symmetries, with suitable n, and one case is generated by a Z2×Z2 symmetry. A numerical analysis of the 14 cases reveals that only two of them—dubbed A and B in the present paper—allow good fits to the experimentally known fermion masses and mixings.