Gauge-Higgs Unification in six dimensions
  Motivated by the pressing problem of the ``little hierarchies'', the possibility of realizing a consistent model of Electroweak Symmetry Breaking via the so-called ``Gauge-Higgs Unification Mechanism'' is discussed. We identify a class of 6 dimensional SU(3) gauge models in which a single Higgs doublet originates from the internal components of the gauge fields. The Higgs mass is beautifully predicted at the tree-level to be twice the $W$-boson mass. At the quantum level, a 1-loop quadratically divergent localized operator is generated and it can contribute to the Higgs mass, reintroducing then the little hierarchy problem. We show that, in some particular case, the presence of this operator does not destabilize the Electroweak Symmetry Breaking Scale and we obtain a framework in which realistic models could be formulated. 
Andrea Wulzer