Abstract
We investigate Higgs-boson pair production at the LHC when the final state system arises from decays of vector-like quarks coupling to the Higgs boson and the Standard Model quarks. Our phenomenological study includes next-to-leading-order QCD corrections, which are important to guarantee accurate predictions, and focuses on a detailed analysis of a di-Higgs signal in the four b-jet channel. Whereas existing Run II CMS and ATLAS analyses are not specifically designed for probing non-resonant, vector-like-quark induced, di-Higgs production, we show that they nevertheless offer some potential for these modes. We then investigate the possibility of distinguishing between the various di-Higgs production mechanisms by exploiting the kinematic properties of the signal.
Highlights
Issued from the fragmentation of bottom quarks, or b-jets, in particular when the pair of Higgs bosons could possibly originate from the decay of a heavier resonance [8,9,10,11,12]
As the four-b-jet signature is associated with the largest branching ratio, we investigate the potential impact of the presence of VLQs on the searches by a study of di-Higgs production and decay into a final state containing four b-jets
We extend our preliminary work performed in the context of the 2015 Les Houches Workshop on TeV Collider Physics [19], and include next-to-leading order (NLO) QCD effects in a study of scenarios in which the sole non-vanishing EW VLQ coupling involves a Higgs boson
Summary
We consider a simplified model where the SM is supplemented by new VLQs that only couple to the Higgs boson and the SM quarks, on top of the usual QCD gauge interactions. It is bounded by experimental data that includes precision measurements in the EW sector [22,23,24], flavour observables [22, 25] and the currently allowed room for deviations in the Higgs sector [26, 27] These constraints on the mixing angles are approximately independent on the mass of the VLQ because they come from lower energy measurements. Even though the mixing angle is in principle inversely proportional to the VLQ mass, we decided to fix its value independently on the VLQ mass With this choice, it turns out to be easier to compare our findings with low energy bounds. We briefly describe in the rest of this section two scenarios where our model configuration featuring exclusive VLQ couplings to the Higgs boson and a light SM quark arises naturally. One of these examples concerns a weakly coupled theory and the other one a strongly coupled theory
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