In this paper we study a new class of supersymmetric models that can explaina 125 GeV Higgs without fine-tuning. These models contain additional `auxiliaryHiggs' fields with large tree-level quartic interaction terms but no Yukawacouplings. These have electroweak-breaking vacuum expectation values, andcontribute to the VEVs of the MSSM Higgs fields either through an inducedquartic or through an induced tadpole. The quartic interactions for theauxiliary Higgs fields can arise from either D-terms or F-terms. The tadpolemechanism has been previously studied in strongly-coupled models with largeD-terms, referred to as `superconformal technicolor.' The perturbative modelsstudied here preserve gauge coupling unification in the simplest possible way,namely that all new fields are in complete SU(5) multiplets. The models areconsistent with the observed properties of the 125 GeV Higgs-like boson as wellas precision electroweak constraints, and predict a rich phenomenology of newHiggs states at the weak scale. The tuning is less than 10% in almost all ofthe phenomenologically allowed parameter space. If electroweak symmetry isbroken by an induced tadpole, the cubic and quartic Higgs self-couplings aresignificantly smaller than in the standard model.
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