Minimal Z′ models and the 125 GeV Higgs boson

The 1-loop renormalization group equations for the minimal Z′ models encompassing a type-I seesaw mechanism are studied in the light of the 125 GeV Higgs boson observation. This model is taken as a benchmark for the general case of singlet extensions of the standard model. The most important result is that negative scalar mixing angles are favored with respect to positive values. Further, a minimum value for the latter exists, as well as a maximum value for the masses of the heavy neutrinos, depending on the vacuum expectation value of the singlet scalar.