[論文レビュー] Weak boson probes of Higgs unitarity restoration at 10 TeV parton colliders

Christoph Englert, Wrishik Naskar+2 more|arXiv (Cornell University)|Jan 20, 2026

Particle physics theoretical and experimental studies被引用数 0

ひとこと要約

論文は FCC-hh（100 TeV）と 10 TeV のμ衝撃コライダーを比較し、ヒッグス結合偏差によって誘発される弱結合体のユニタリティ回復共振の発見可能性を評価。多 TeV 共有振動で比較可能な探索ポテンシャルを示す。

ABSTRACT

Higgs coupling deviations, at levels accessible to the high-luminosity LHC, can imply a phenomenological no-lose theorem for the next generation of collider facilities. Correlating Higgs coupling deviations from the SM expectation in the gauge boson sector with high-scale unitarity requirements, we estimate and compare the sensitivity that can be expected at a future hadron collider (operating at 100 TeV centre-of-mass energy) and a 10 TeV muon collider. Both muon and hadron colliders offer discovery potential for mass scales up to ${\cal{O}}(6~ ext{TeV})$ where unitarity violation induced by (sub)percent Higgs coupling modifications is mended. We comment on how an intermediate precision FCC-ee programme can corroborate such deviations.

研究の動機と目的

• Motivate a no-lose-theorem perspective: Higgs coupling deviations imply accessible unitarity-restoring resonances at future colliders.
• Relate high-scale unitarity restoration to observable resonances in WBF processes.
• Provide a comparative sensitivity assessment for a 10 TeV muon collider and a 100 TeV FCC-hh.
• Explore how different resonance types (scalar vs vector) and Higgs coupling deviations affect discovery potential.

提案手法

• Model unitarity-restoring scenarios with minimal extra states beyond the SM: a heavy scalar H' or iso-triplet vector resonances W', Z'.
• Translate unitarity sum rules into benchmark couplings and widths of new resonances as a function of Higgs coupling modifier kappa_H (or mu_H).
• Simulate WBF processes (WW, WZ, ZZ) with resonant and non-resonant contributions using MadGraph5_aMC@NLO and a FeynRules/UFO model.
• Assess resonant signatures in leptonic and semi-leptonic final states with jet tagging, invariant mass and transverse mass distributions as primary observables.
• Estimate significances S/√B for reach, considering backgrounds from non-resonant WBS and higher-order VVjj processes and collider-specific backgrounds.

Figure 1: Feynman diagram contributions to the $s$ channel of $WW\to WW$ scattering (suppressing $t$ topologies). Similar diagrams exist for $WZ$ scattering with $W$ resonances appearing as $s$ and $t$ channel contributions.

実験結果

リサーチクエスチョン

• RQ1 What is the discovery reach for unitarity-restoring resonances (H', W', Z') as a function of Higgs coupling deviations μ_H < 1 at a 10 TeV muon collider and a 100 TeV FCC-hh?
• RQ2 How do scalar vs vector unitarity-restoring scenarios compare in terms of observable signals in WW, WZ, and ZZ weak-boson fusion channels at these colliders?
• RQ3 How does resonance width (e.g., Γ/m = 2.5% vs 10%) influence the sensitivity and channel optimization at each collider?
• RQ4 What are the implications of fermion couplings of new resonances for the visibility of Z' and W' signals in WBF channels?
• RQ5 Can intermediate precision e+e− programs (FCC-ee) corroborate or constrain the Higgs coupling deviations before or alongside hadron/muon collider discoveries?

主な発見

• Both facilities show potential to observe scalar resonances up to about 6 TeV under the studied benchmarks.
• Muon collider benefits from fully hadronic W decays enabling direct diboson mass reconstruction and reduced background, yielding competitive sensitivity with FCC-hh for narrow resonances.
• FCC-hh sensitivity is strong for Z' when couplings to fermions are suppressed (fermiophobic case), achieving reach up to ~7 TeV for μ_H near 0.95–0.99.
• Sensitivity to W' resonances is similar between colliders, with reach around 2.5–4 TeV depending on μ_H and width assumptions.
• Fermion couplings of Z' (e.g., to tt̄) can dramatically affect Z' decay widths and observed rates, potentially reducing collider reach.