Impact of Higgs precision measurements at the LHC and FCC-ee on the spectrum of composite Higgs models
- 1Shahrood University of Technology
- 2Sorbonne Université and CNRS
Abstract
We investigate the minimal composite Higgs model based on the symmetry-breaking pattern SU(4)→ Sp(4), where electroweak symmetry breaking is governed by the vacuum alignment angle θ . Through the leading-order relations κ V=cos θ and mη =mh/sin θ , precision measurements of Higgs couplings constrain the vacuum structure and, within this leading-order realization, the singlet pseudo-Nambu–Goldstone boson mass. Using the current ATLAS Run-2 measurement of κ V, we construct a Bayesian posterior for θ , including the Jacobian from the transformation κ V→ θ (assuming a flat prior in κ V). We cross-check these results with an independent frequentist Δ χ 2 analysis; the two approaches yield consistent bounds on θ. The same framework is applied to the projected sensitivities of the High-Luminosity LHC and FCC-ee. The current data imply a lower bound of approximately 440 GeV on the singlet mass at the 95% credibility level, conservative under the flat prior in κ V with boundary truncation. The HL-LHC improves this to about 600 GeV, while FCC-ee reaches beyond 2 TeV as an indicative projected sensitivity. While the constraint on θ is comparatively model-independent, these mη bounds hold within the specific leading-order potential considered here. Our results show that future Higgs precision measurements will probe the vacuum alignment of the minimal SU(4)/Sp(4) composite Higgs model with unprecedented sensitivity. They place increasingly stringent indirect constraints on the singlet mass, whose direct collider phenomenology depends on additional model-dependent couplings.
Related
- Prospects for precision Higgs boson measurements at a 10 TeV muon collider
- Colour sextet baryons in composite Higgs models
- Toward a Measurement of the Higgs Boson Mass with Natural-Width Precision at FCC-ee
- The Super-Composite Higgs
- Combination of Higgs boson measurements at √s = 13 TeV and their interpretations by the ATLAS experiment
BibTeX
@article{jelodar2026impact,
title = {{Impact of Higgs precision measurements at the LHC and FCC-ee on the spectrum of composite Higgs models}},
author = {Reza Asgharzadeh Jelodar and Kazem Bitaghsir Fadafan and Giacomo Cacciapaglia},
journal = {The European Physical Journal C},
year = {2026},
month = nov,
doi = {10.1140/epjc/s10052-026-16487-1},
url = {https://link.springer.com/article/10.1140/epjc/s10052-026-16487-1},
note = {CC BY 4.0},
}
RIS
TY - JOUR
TI - Impact of Higgs precision measurements at the LHC and FCC-ee on the spectrum of composite Higgs models
AU - Reza Asgharzadeh Jelodar
AU - Kazem Bitaghsir Fadafan
AU - Giacomo Cacciapaglia
PY - 2026
DA - 2026/11/09
JO - The European Physical Journal C
DO - 10.1140/epjc/s10052-026-16487-1
UR - https://link.springer.com/article/10.1140/epjc/s10052-026-16487-1
AB - We investigate the minimal composite Higgs model based on the symmetry-breaking pattern SU(4)→ Sp(4), where electroweak symmetry breaking is governed by the vacuum alignment angle θ . Through the leading-order relations κ _V=cos θ and m_η =m_h/sin θ , precision measurements of Higgs couplings constrain the vacuum structure and, within this leading-order realization, the singlet pseudo-Nambu–Goldstone boson mass. Using the current ATLAS Run-2 measurement of κ _V, we construct a Bayesian posterior for θ , including the Jacobian from the transformation κ _V→ θ (assuming a flat prior in κ _V). We cross-check these results with an independent frequentist Δ χ ^2 analysis; the two approaches yield consistent bounds on θ. The same framework is applied to the projected sensitivities of the High-Luminosity LHC and FCC-ee. The current data imply a lower bound of approximately 440 GeV on the singlet mass at the 95% credibility level, conservative under the flat prior in κ _V with boundary truncation. The HL-LHC improves this to about 600 GeV, while FCC-ee reaches beyond 2 TeV as an indicative projected sensitivity. While the constraint on θ is comparatively model-independent, these m_η bounds hold within the specific leading-order potential considered here. Our results show that future Higgs precision measurements will probe the vacuum alignment of the minimal SU(4)/Sp(4) composite Higgs model with unprecedented sensitivity. They place increasingly stringent indirect constraints on the singlet mass, whose direct collider phenomenology depends on additional model-dependent couplings.
SN - 1434-6052
ER -