Electroweak Symmetry Breaking via QCD

TL;DR

The paper proposes a non-perturbative mechanism to generate the electroweak scale by extending QCD with a colored scalar $S$ in a large SU(3)_c representation. EW symmetry breaking is triggered when $S$ condenses at a TeV scale according to the criterion $C_2(S)\alpha(\Lambda)\gtrsim 1$, with the condensate entering the Higgs portal to yield a Higgs mass term $m_h^2=2\lambda_{HS}\Lambda^2$. For the $m{15'}$ representation, this framework constrains the mass of $S$ to $350~\mathrm{GeV} \lesssim m_S \lesssim 3~\mathrm{TeV}$ via RG considerations, placing it within LHC reach, and predicts potential modifications to Higgs production and diphoton decays depending on the hypercharge assignment. The approach links non-perturbative QCD dynamics to electroweak symmetry breaking and offers a novel starting point for building models addressing the hierarchy problem, with clear collider signatures and avenues for testing confinement dynamics. Overall, the work highlights a unique route to EW scale generation through scalar QCD condensation and Higgs-portal interactions, motivating further non-perturbative analyses and phenomenological studies.

Abstract

We propose a new mechanism to generate the electroweak scale within the framework of QCD, which is extended to include conformally invariant scalar degrees of freedom belonging to a larger irreducible representation of $SU(3)_c$. The electroweak symmetry breaking is triggered dynamically via the Higgs portal by the condensation of the colored scalar field around 1 TeV. The mass of the colored boson is restricted to be 350 GeV $\lesssim m_S\lesssim $ 3 TeV, with the upper bound obtained from perturbative renormalization group evolution. This implies that the colored boson can be produced at LHC. If the colored boson is electrically charged, the branching fraction of the Higgs decaying into two photons can slightly increase, and moreover, it can be produced at future linear colliders. Our idea of non-perturbative EW scale generation can serve as a new starting point for more realistic model building in solving the hierarchy problem.

Figures (3)

• Figure 1: The Higgs production cross section from gluon fusion channel at NLO is calculated for different values of $\lambda_{HS}$. The solid (dashed) curves represent the prediction of $\sigma(gg\rightarrow H)$ at $\sqrt{s}=\unit[14]{TeV}$ ($\unit[8]{TeV}$). The combined signal strength $\mu$ for ATLAS ATLAS:2013mma and CMS CMS:yva is shown where we have assumed a SM-like BR.
• Figure 2: The $S$ pair production cross section from gluon fusion channel is calculated for different value of $m_S$. The $95\%$ confidence level exclusion limit on $\sigma \times \mathrm{BR}$ for $\sqrt{s}=\unit[7]{TeV}$ by ATLAS is plotted. We assume $100\%$ BR of $\langle S^\dagger S \rangle$ into two jets.
• Figure 3: The signal strength of $H\rightarrow \gamma \gamma$ branching ratio with the additional $S$ contribution relative to the SM prediction are plotted for different values of electric charge $e$ and $\lambda_{HS}$ of $S$. The large electric charge has to compensate the suppression of production cross section for $\mu_{\gamma \gamma}$ enhancement.