A minimal Little Higgs model

TL;DR

This paper presents a minimal Little Higgs model featuring a vectorlike T quark and a singlet Higgs component, achieving realistic Higgs and pseudoscalar masses without extra parameters, and exploring its phenomenological implications.

Contribution

It introduces a simplified Little Higgs model with only essential ingredients, analyzing its effective potential and mass spectrum, differing from more complex models.

Findings

The model yields acceptable Higgs and ta masses without a ta decay mode.

All extra vector bosons are significantly heavier than the T quark.

The effective potential is computed at one loop, ensuring realistic scalar masses.

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.