CERN Accelerating science

Preprint
Report number	CERN-EP-2025-229
Title	Differential cross-section measurements of coherent production of singly and doubly resonant top-quark in $WWbb$ events with one lepton at $\sqrt{s}$ = 13 TeV with the ATLAS detector
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Corporate author(s)	ATLAS Collaboration
Publication	2025
Collaboration	ATLAS Collaboration
Imprint	03 Nov 2025
Subject category	Particle Physics - Experiment
Accelerator/Facility, Experiment	CERN LHC ; ATLAS
Keywords	flavor physics ; QCD ; top physics ; heavy quark production ; top quark ; tW
Abstract	This paper presents differential cross-section measurements of events containing a charged lepton, missing transverse momentum, two $b$-jets, and two light jets, consistent with the $W^{+}W^{-}b\bar{b}$ final state. The analysis is based on 140 fb$^{-1}$ of proton-proton collision data at $\sqrt{s}$ = 13 TeV recorded with the ATLAS detector during Run 2 of the Large Hadron Collider(2015-2018). Differential cross-sections are unfolded at particle level for a range of kinematic observables and in three kinematic regions. Both regions and observables are optimised for sensitivity to the interference between $W^{+}W^{-}b\bar{b}$ produced with singly and doubly resonant top quarks. Results are compared with various theoretical predictions. Significant discrepancies are observed in regions sensitive to the interference between singly and doubly resonant top-quark production. The unfolded results provide new information about the modelling of interference and off-shell effects of the $W^{+}W^{-}b\bar{b}$ final state, improving the understanding of top-quark production mechanisms and providing new inputs for future Monte Carlo generator development.
Copyright/License	Preprint: © 2025 CERN (License: CC-BY-4.0)
Submitted by	tatjana.lenz@cern.ch