Measurement of the top-quark Yukawa coupling from t t ¯ production in the lepton+jets final state using pp collisions at s = 13 TeV with the ATLAS detector

Journal article

The top-quark Yukawa coupling is extracted from the distribution of the top-quark pair (tt¯) invariant mass in proton-proton collisions using 140 fb−1 of data at s=13 TeV collected in 2015–2018 by the ATLAS experiment at the Large Hadron Collider. In the region near the production threshold, the tt¯ invariant mass spectrum is sensitive to electroweak virtual corrections, including contributions from Higgs boson exchange, thereby providing sensitivity to the top-quark Yukawa coupling. This is the first measurement in ATLAS that aims to obtain this coupling exploiting this approach. The tt¯ system is reconstructed in the single-lepton final state, requiring exactly one isolated electron or muon and at least four jets with at least two identified as originating from b-quarks. The measured Yukawa coupling is found to be in good agreement with the Standard Model prediction. An upper limit on the top-quark Yukawa coupling strength of Yt< 2.1 relative to the Standard Model prediction is observed at 95% confidence level, consistent with the expected sensitivity.

Authors: Aad, G; Aakvaag, E; Abbott, B; Abdelhameed, S; Abeling, K

• Publication status: Published
• Peer review status: Peer reviewed
• Publisher: Springer
• Journal: Journal of High Energy Physics
• Volume: 2026
• Issue: 1
• Article number: 117
• Publication date: 2026-01-19
• Acceptance date: 2025-11-08
• DOI: 10.1007/jhep01(2026)117
• EISSN: 1029-8479
• ISSN: 1126-6708
• Language: English
• Keywords: Hadron-Hadron Scattering; Higgs Physics; Top Physics