Seesaw induced Higgs Mechanism

We discuss a two scalar doublets model which induces the Higgs mechanism by means of a seesaw mechanism. This model naturally predicts a light Higgs scalar whose mass is suppressed by the grand unification scale. The model predicts an intermediate scale between the electroweak symmetry breaking scale and the grand unification scale at 10 GeV. Below this intermediate energy scale the usual standard model appears as an effective theory. A seesaw mechanism in the scalar sector of the model not only induces the standard Higgs mechanism, but also solves the hierarchy problem. An implementation of this mechanism in models where the Planck scale is in the TeV region is discussed. supported by the Deutsche Forschungsgemeinschaft, DFG-No. FR 412/27-2, email:[email protected] The electroweak symmetry breaking in the standard model [1], which is a gauge theory based on the structure group SU(3) × SU(2) × U(1), is implemented by means of the Higgs mechanism [2]. If the standard model is embedded into a grand unified theory like e.g. SU(5) [3] or SO(10) [4], it suffers from two problems that have often been discussed in the literature. The running of the coupling constant of the standard model suggests that the unification is taking place at a grand unification scale ΛGUT ≈ 10 GeV. The gauge hierarchy problem states that it is unnatural for the electroweak breaking scale ΛEW ≈ 174 GeV to be so small compared to the fundamental scale ΛGUT . A second potential problem with the standard model is that the Higgs boson is an elementary scalar field. It is useful, in order to get some intuition, to regularize the theory using a cutoff Λ. One finds that the Higgs squared boson mass m2H receives quadratic “corrections” m2H ≈ m0H 2 + (1)