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

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 -> t(2)(t) over bar (2), t(2) -> th, allows to discover a Higgs boson at the LHC and measure its mass, through the decay channels h -> gamma gamma or h -> ZZ. We also comment on the recent hint in LHC data from a possible similar to 125 GeV Higgs scalar, in the presence of heavy vectorlike top quarks.