A minimal Little Higgs model

Abstract

We discuss a Little Higgs scenario that introduces below the TeV scale just the two minimal ingredients of these models, a vectorlike T quark and a singlet component (implying anomalous couplings) in the Higgs field, together with a pseudoscalar singlet \eta. In the model, which is a variation of Schmaltz's simplest Little Higgs model, all the extra vector bosons are much heavier than the T quark. In the Yukawa sector the global symmetry is approximate, implying a single large coupling per flavour, whereas in the scalar sector it is only broken at the loop level. We obtain the one-loop effective potential and show that it provides acceptable masses for the Higgs h and for the singlet \eta with no need for an extra \mu term. We find that m_\eta can be larger than m_h/2, which would forbid the (otherwise dominant) decay mode h -> \eta\eta.