2025 Articles

Measurement of the associated production of a top-antitop-quark pair and a Higgs boson decaying into a 𝑏𝑏̄ pair in 𝑝𝑝 collisions at √𝒔 = 13 TeV using the ATLAS detector at the LHC

Al Khoury, Konie; Angerami, Aaron; Brooijmans, Gustaaf H.; Busch, Elena Laura; Cole, Brian A.

This paper reports the measurement of Higgs boson production in association with a 𝑡𝑡̄ pair in the 𝐻 → 𝑏𝑏̄ decay channel. The analysis uses 140 fb⁻¹ of 13 TeV proton–proton collision data collected with the ATLAS detector at the Large Hadron Collider. The final states with one or two electrons or muons are employed. An excess of events over the expected background is found with an observed (expected) significance of 4.6 (5.4) standard deviations.

The 𝑡𝑡̄𝐻 cross-section is 𝜎_𝑡𝑡̄𝐻 = 411⁺¹⁰¹₋₉₂fb = 411±54(stat.)⁺⁸⁵₋₇₅(syst.) fb for a Higgs boson mass of 125.09 GeV, consistent with the prediction of the Standard Model of 507⁺³⁵₋₅₀ fb. The cross-section is also measured differentially in bins of the Higgs boson transverse momentum within the simplified template cross-section framework.