A measurement of the associated production of a top-quark pair with the Higgs boson (tt¯H) in multilepton final states is presented. The analysis is based on a data sample of proton-proton collisions at s=13 TeV recorded with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 140 fb−1. Six final states defined by the number and flavour of reconstructed charged leptons are combined in a simultaneous likelihood fit to extract the tt¯H signal and constrain the most relevant backgrounds. The measured tt¯H cross-section normalised to Standard Model (SM) prediction is σtt¯H/σSM=0.63−0.19+0.20. This result corresponds to an observed (expected) significance of 3.3σ (5.3σ). Additionally, two other fits are used to measure the tt¯H cross-section differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, and to extract the associated production cross-section of a single top-quark with the Higgs boson (tH) together with the tt¯H one. The CP structure of the top quark-Higgs boson Yukawa coupling is probed through an analysis of tt¯H and tH events. The results are compatible with the SM hypothesis, and values of the mixing angle between CP-even and CP-odd top-Higgs Yukawa couplings of |α| > 62° are excluded at 68% confidence level.

Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). Measurement of the Higgs boson production in association with top quarks in multilepton final states in pp collisions at sqrt(s)=13 TeV with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2026(5) [10.1007/jhep05(2026)183].

Measurement of the Higgs boson production in association with top quarks in multilepton final states in pp collisions at sqrt(s)=13 TeV with the ATLAS detector

Di Micco, B.;Di Nardo, R.;Montereali, F.;Orestano, D.;Orlandini, R.;
2026-01-01

Abstract

A measurement of the associated production of a top-quark pair with the Higgs boson (tt¯H) in multilepton final states is presented. The analysis is based on a data sample of proton-proton collisions at s=13 TeV recorded with the ATLAS detector at the CERN Large Hadron Collider and corresponding to an integrated luminosity of 140 fb−1. Six final states defined by the number and flavour of reconstructed charged leptons are combined in a simultaneous likelihood fit to extract the tt¯H signal and constrain the most relevant backgrounds. The measured tt¯H cross-section normalised to Standard Model (SM) prediction is σtt¯H/σSM=0.63−0.19+0.20. This result corresponds to an observed (expected) significance of 3.3σ (5.3σ). Additionally, two other fits are used to measure the tt¯H cross-section differentially in bins of the Higgs boson transverse momentum in the simplified template cross-section framework, and to extract the associated production cross-section of a single top-quark with the Higgs boson (tH) together with the tt¯H one. The CP structure of the top quark-Higgs boson Yukawa coupling is probed through an analysis of tt¯H and tH events. The results are compatible with the SM hypothesis, and values of the mixing angle between CP-even and CP-odd top-Higgs Yukawa couplings of |α| > 62° are excluded at 68% confidence level.
2026
Aad, G., Aakvaag, E., Abbott, B., Abdelhameed, S., Abeling, K., Abicht, N.J., et al. (2026). Measurement of the Higgs boson production in association with top quarks in multilepton final states in pp collisions at sqrt(s)=13 TeV with the ATLAS detector. JOURNAL OF HIGH ENERGY PHYSICS, 2026(5) [10.1007/jhep05(2026)183].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11590/560418
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