Little Higgs models with a light T quark

We study little Higgs models based on a SU(3)(1) x SU(3)(2) global symmetry and with two scales (the two vacuum expectation values f(1,2)) substantially different. We show that all the extra vector boson fields present in these models may be much heavier than the vectorlike T quark necessary to cancel top-quark quadratic corrections. In this case the models become an extension of the Standard Model with a light (approximate to 500 GeV) T quark and a scalar Higgs field with a large singlet component. We obtain that the Yukawa and the gauge couplings of the Higgs are smaller than in the standard model, a fact that may reduce significantly the Higgs production rate through glu-glu and WW fusion. The T quark decay into Higgs boson becomes then the dominant Higgs production channel in hadron colliders. (C) 2007 Elsevier B.V. All rights reserved.