Sigma-assisted low scale composite Goldstone–Higgs

Abstract

We show that the presence of a lightish scalar resonance, σ , that mixes with the composite Goldstone-Higgs boson can relax the typical bounds found in this class of models. This mechanism, inbred in models with a walking dynamics above the condensation scale, allows for a low compositeness scale f 400 GeV, corresponding to a misalignment angle s θ 0.6, contrary to the common lore of a smaller angle. According to recent lattice results, the light σ emerges thanks to a near-conformal phase above the condensation scale, consistent to the requirements from flavour physics. We study this effect in a general way, showing that it appears in all cosets emerging from an underlying gauge-fermion dynamics, in the presence of top partial compositeness. The scenario is testable both on the Lattice and experimentally, as it requires the presence of a second broad Higgs-like resonance, below 1 TeV, that can be revealed at the LHC in the Z Z and tt channels.

Holographic conformal transition and light scalars

“…We only point out several interesting features. First, the lightness of the dilaton can have important implications for the LHC [44][45][46]. Also the fact that the mass of a 1 is closer to the mass of ρ implies smaller values for the S-parameter (this was also pointed out in ref.…”

Review on Composite Higgs Models

“…we choose N h such that a theory with N + N h degenerate flavors is conformal. In the case of SU(3) with N = 4 light flavors, the model can be embedded in a fundamental composite two Higgs doublet model (2HDM) [78,79]. Moreover, the heavy flavors could be invisible to the SM.…”

Automated predictions from polarized matrix elements

“…Direct measurements of Higgs couplings constrain a at the 95% CL to be a 0.9 [107]. Indirect EW precision data also require a 0.98 [108], but can be relaxed if additional assumptions are satisfied [109].…”