Top quark couplings at the muon collider
Abstract
We present an overview of the sensitivity of a muon collider to the flavor-diagonal electroweak couplings of the top quark, using dimension-six operators of the Warsaw basis. Of the nine fermion-boson operators involving the top quark, the bounds on three are not competitive with existing limits, and we focus on the remaining six. We estimate individual 95% CL limits on the corresponding Wilson coefficients at √s = 3, $6$, $10$, and $14$~TeV from 2σ statistical cross-section uncertainties, and assess the effect of an assumed systematic uncertainty. We consider six top-quark production modes: tt̅, t t̅ h, t t̅ νν̅, t t̅ μ+ μ-, single-top tb̅ μ- ν̅μ, and single-top-plus-Higgs, the last three for several rapidity coverages of the final-state muons. The s-channel tt̅ and tt̅ h processes give the strongest sensitivity to the electroweak dipole couplings, with allowed intervals narrower than the current LHC ones by factors of about $3$ to $6$ at √s = 3 and $6$ TeV, and by an order of magnitude or more at $10$ and $14$ TeV. The left- and right-handed ttZ couplings, as well as the Yukawa tth couplings (for √s ≥ 6 TeV), are best probed in t t̅ νν̅ production, while the right-handed tbW coupling is best probed in single-top production. For the ttZ and tbW couplings, the limits improve on the current LHC bounds by factors from about $1.5$ to more than an order of magnitude. Our results agree with previous analyses of the Yukawa and the dipole couplings, and provide a roadmap for more in-depth studies.
Related
- Input to the SCAC Facilities Subcommittee from the U.S. Muon Collider Collaboration
- Dihadron azimuthal asymmetry and light-quark dipole moments at the Electron-Ion Collider
- FCC-μe: High Energy, High Luminosity Muon-Electron Collider & Neutrino Factory at CERN
- Vanilla Scotogenic Model at the future Muon Collider
- Report of the National Lab Accelerator Study Group for a Muon Collider
BibTeX
@misc{urcelay2026quark,
title = {{Top quark couplings at the muon collider}},
author = {Nicolás Urcelay and Antonio O. Bouzas and F. Larios},
howpublished = {arXiv},
year = {2026},
month = nov,
doi = {10.48550/arxiv.2611.00349},
eprint = {2611.00349},
archivePrefix = {arXiv},
url = {https://arxiv.org/abs/2611.00349},
note = {CC BY 4.0},
}
RIS
TY - UNPB
TI - Top quark couplings at the muon collider
AU - Nicolás Urcelay
AU - Antonio O. Bouzas
AU - F. Larios
PY - 2026
DA - 2026/11/01
PB - arXiv
DO - 10.48550/arxiv.2611.00349
UR - https://arxiv.org/abs/2611.00349
AB - We present an overview of the sensitivity of a muon collider to the flavor-diagonal electroweak couplings of the top quark, using dimension-six operators of the Warsaw basis. Of the nine fermion-boson operators involving the top quark, the bounds on three are not competitive with existing limits, and we focus on the remaining six. We estimate individual 95% CL limits on the corresponding Wilson coefficients at √s = 3, $6$, $10$, and $14$~TeV from 2σ statistical cross-section uncertainties, and assess the effect of an assumed systematic uncertainty. We consider six top-quark production modes: tt̅, t t̅ h, t t̅ νν̅, t t̅ μ^+ μ^-, single-top tb̅ μ^- ν̅_μ, and single-top-plus-Higgs, the last three for several rapidity coverages of the final-state muons. The s-channel tt̅ and tt̅ h processes give the strongest sensitivity to the electroweak dipole couplings, with allowed intervals narrower than the current LHC ones by factors of about $3$ to $6$ at √s = 3 and $6$ TeV, and by an order of magnitude or more at $10$ and $14$ TeV. The left- and right-handed ttZ couplings, as well as the Yukawa tth couplings (for √s ≥ 6 TeV), are best probed in t t̅ νν̅ production, while the right-handed tbW coupling is best probed in single-top production. For the ttZ and tbW couplings, the limits improve on the current LHC bounds by factors from about $1.5$ to more than an order of magnitude. Our results agree with previous analyses of the Yukawa and the dipole couplings, and provide a roadmap for more in-depth studies.
ER -