Strong Coupling Electroweak Symmetry Breaking

TL;DR

The paper surveys the landscape of electroweak symmetry breaking driven by new strong interactions at the TeV scale, emphasizing direct tests via high-energy vector-boson scattering and complementary probes such as the pion form factor and top quark couplings. It integrates model‑independent signatures with detailed examinations of technicolor, walking technicolor, and topcolor‑assisted scenarios, outlining experimental strategies for the LHC and a future e+e− collider (NLC) to detect resonances, measure cross sections, and analyze polarization. The analysis demonstrates that the LHC can discover strong‑interaction EWSB through diboson channels and that the NLC can perform precision measurements of the I=1 channel and top coupling, while also highlighting the challenges and the need for very high energies to map the full resonance structure. The work also discusses exotic states (technipions, technirhos, topcolor bosons) and their collider reach, underscoring the breadth of signatures required to validate or refute these strong‑coupling frameworks. Overall, it provides a roadmap for probing TeV‑scale strong dynamics with current and near‑term colliders and outlines the path to deeper exploration at future high‑energy facilities.

Abstract

We review models of electroweak symmetry breaking due to new strong interactions at the TeV energy scale and discuss the prospects for their experimental tests. We emphasize the direct observation of the new interactions through high-energy scattering of vector bosons. We also discuss indirect probes of the new interactions and exotic particles predicted by specific theoretical models. [Working group summary report from the Snowmass `96 summer study, to appear in the proceedings.]

Figures (17)

• Figure 1: The Goldstone Boson Equivalence Theorem.
• Figure 2: Processes which measure the pion-pion scattering amplitudes of new strong interactions.
• Figure 3: Dependence of $F_\pi(q^2)$ on energy, in models without and with a new strong interaction resonance in the $I$=$J$=1 channel.
• Figure 4: Reconstructed masses for high mass resonances decaying into gauge boson pairs, from atlas: (a) Signal of a 1 TeV $\rho_T$ decaying to $WZ$ and subsequently to three leptons (b) Signal of a 1.46 TeV $\omega_T$ decaying to $Z\gamma$ with the $Z$ then decaying to two leptons.
• Figure 5: Expected numbers of $W^+W^+ \rightarrow (l\nu)(l\nu)$ signal and background events after all cuts for a 100 fb$^{-1}$ data sample at the LHC, from atlas. The signal corresponds to a 1 TeV Higgs.