Higgs boson production via vectorlike top-partner decays: Diphoton or multilepton plus multijets channels at the LHC

Abstract

We first build a minimal model of vectorlike quarks where the dominant Higgs boson production process at LHC---the gluon fusion---can be significantly suppressed, being motivated by the recent stringent constraints from the search for direct Higgs production over a wide Higgs mass range. Within this model, compatible with the present experimental constraints on direct Higgs searches, we demonstrate that the Higgs ($h$) production via a heavy vectorlike top-partner (${t}_{2}$) decay, $pp\ensuremath{\rightarrow}{t}_{2}{\overline{t}}_{2}$, ${t}_{2}\ensuremath{\rightarrow}th$, allows to discover a Higgs boson at the LHC and measure its mass, through the decay channels $h\ensuremath{\rightarrow}\ensuremath{\gamma}\ensuremath{\gamma}$ or $h\ensuremath{\rightarrow}ZZ$. We also comment on the recent hint in LHC data from a possible $\ensuremath{\sim}125\text{ }\text{ }\mathrm{GeV}$ Higgs scalar, in the presence of heavy vectorlike top quarks.