In many extensions of the standard model, the Higgs sector often contains an additional pseudoscalar boson. A good example is the SU(3) simplest little Higgs model, which accommodates a light pseudoscalar boson $\eta$ with quite different characteristics from those in other multi-Higgs-doublet models. We study various phenomenological signatures of the $\eta$ at the CERN LHC. In particular, we calculate in details both production and decays in the Drell-Yan type channel $q\overline{q}\to Z/Z^{\prime }\to h\eta$, and in the associated production with a $t\overline{t}$ pair, $gg(q\overline{q})\to t\overline{t}\eta$. We emphasize the ${\tau }^{+}{\tau }^{-}$ decay mode of the $\eta$ boson when its mass is below the $b\overline{b}$ threshold. We show that $t\overline{t}\eta$ production is in fact large enough to give a sizable number of events while suppressing the backgrounds. We also comment on the direct gluon fusion process and the indirect decay from the heavy $T$ quark ($T\to t\eta$).

• Received 8 July 2008

DOI:https://doi.org/10.1103/PhysRevD.78.055015