The limits on the strong Higgs sector parameters in the presence of new vector resonances

Abstract

In this paper, we investigate how the LHC data limit the Higgs-related couplings in the effective description of a strongly interacting extension of the Standard model. The Higgs boson is introduced as a scalar composite state and it is followed in the mass hierarchy by an SU (2) triplet of vector composites. The limits are calculated from the constraints obtained in the recent ATLAS+CMS combined analysis of the data from 2011 and 2012. We find that the data prefer the scenario where the Higgs couplings to the electroweak gauge bosons differ from its couplings to the vector triplet. We also investigate the unitarity limits of the studied effective model for the experimentally preferred values of the Higgs couplings. We find from the ππ → ππ scattering amplitudes that for the vector resonance masses between one and two TeV significant portions of the experimentally allowed regions are well below the unitarity limit. We also evaluate how the existing ATLAS and CMS Run-2 data restrict our model with the upper bounds on the resonance production cross section times its branching ratio for various decay channels. The masses in the range 1 TeV ≤ M ρ ≤ 2 TeV are not excluded in parts or even full parameter space of our theory.

A case study about the mass exclusion limits for the BSM vector resonances with the direct couplings to the third quark generation

“…Throughout this paper, we set a V = 1 (the SM case) and a ρ = 0 (no Higgs-to-vector resonance coupling). These values are consistent with the experimentally preferred points of the parameter space [6]. This choice that zeros the Hρ 0 ρ 0 and Hρ + ρ − vertices and sets the HW W and HZZ vertices to their SM form has no impact on our analysis.…”

“…Usually, α is traded off for M ρ so that the latter can serve as one of the free parameters of the model. Our previous studies of the lowenergy limits [4,5] as well as the Higgs-related limits and the unitarity limits [6] suggest that we should consider M ρ ≥ 1 TeV and 12 ≤ g ′′ ≤ 25. Following the conventions used in the formulation of our Lagrangian the naive perturbativity bound on g ′′ reads g ′′ /2 ≤ 4π.…”

“…The effective Lagrangian, we use in this paper, was studied in detail in our previous papers [4][5][6]. It can serve as an effective description of the LHC phenomenology of a hypothetical strongly interacting extension of the SM where the principal manifestation of this scenario would be the existence of a vector resonance triplet as a bound state of new strong interactions.…”

“…Beside the scalar singlet representing the 125 GeV Higgs boson and the hypothetical vector triplet, the effective Lagrangian is built out of the SM fields only. The effective Lagrangian itself can be found in [4][5][6].…”

“…The Hρ 0 ρ 0 and Hρ + ρ − couplings are virtually proportional to a ρ . The corresponding interaction Lagrangian, along with the calculations of the LHC experimental limits for a V and a ρ , can be found in [6].…”