Measurements of inclusive and differential fiducial cross-sections of $t\bar{t}\gamma$ production in leptonic final states at $\sqrt{s}$ = 13 TeV in ATLAS

Abstract

Inclusive and differential cross-sections for the production of a top-quark pair in association with a photon are measured with proton-proton collision data corresponding to an integrated luminosity of 36.1 fb${}^{-1}$, collected by the ATLAS detector at the LHC in 2015 and 2016 at a centre-of-mass energy of 13 TeV. The measurements are performed in single-lepton and dilepton final states in a fiducial volume. Events with exactly one photon, one or two leptons, a channel-dependent minimum number of jets, and at least one $b$-jet are selected. Neural network algorithms are used to separate the signal from the backgrounds. The fiducial cross-sections are measured to be 521 $\pm$ 9(stat.) $\pm$ 41(sys.) fb and 69 $\pm$ 3(stat.) $\pm$ 4(sys.) fb for the single-lepton and dilepton channels, respectively. The differential cross-sections are measured as a function of photon transverse momentum, photon absolute pseudorapidity, and angular distance between the photon and its closest lepton in both channels, as well as azimuthal opening angle and absolute pseudorapidity difference between the two leptons in the dilepton channel. All measurements are in agreement with the theoretical predictions.

56 pages in total, author list starting page 40, 17 figures, 9 tables, submitted to EPJC. All figures, including auxiliary figures, are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/TOPQ-2017-14

References in corpus (15)

• Batch Normalization: Accelerating Deep Network Training by Reducing Internal Covariate Shift
• The automated computation of tree-level and next-to-leading order differential cross sections, and their matching to parton shower simulations
• An Introduction to PYTHIA 8.2
• Parton distributions for the LHC
• Matching NLO QCD computations with Parton Shower simulations: the POWHEG method
• New parton distributions for collider physics
• Event generation with SHERPA 1.1
• The Catchment Area of Jets
• Luminosity determination in pp collisions at $\sqrt{s}$ = 8 TeV using the ATLAS detector at the LHC
• Jet energy measurement and its systematic uncertainty in proton-proton collisions at $\sqrt{s}=7$ TeV with the ATLAS detector
• Electron reconstruction and identification in the ATLAS experiment using the 2015 and 2016 LHC proton-proton collision data at $\sqrt{s}$ = 13 TeV
• Electron and photon energy calibration with the ATLAS detector using 2015-2016 LHC proton-proton collision data
• Observation of top-quark pair production in association with a photon and measurement of the $t\bar{t}\gamma$ production cross section in pp collisions at $\sqrt{s}=7$ TeV using the ATLAS detector
• Measurement of the semileptonic tt-bar gamma production cross section in pp collisions at sqrt(s) = 8 TeV
• Measurement of the $t\bar{t}\gamma$ production cross section in proton-proton collisions at $\sqrt{s}=8$ TeV with the ATLAS detector

Cited by in corpus (22)

• Measurement of the $t\bar{t}Z$ and $t\bar{t}W$ cross sections in proton-proton collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Testing new physics models with global comparisons to collider measurements: the Contur toolkit
• Constraining top-quark couplings combining top-quark and $\mathbf{B}$ decay observables
• Search for new phenomena in two-body invariant mass distributions using unsupervised machine learning for anomaly detection at $\sqrt{s}=13$ TeV with the ATLAS detector
• Automated EW corrections with isolated photons: $t\bar{t}\gamma$, $t\bar{t}\gamma \gamma$ and $t\gamma j$ as case studies
• Measurement of the $Z(\to {\ell }^{+}{\ell }^{-})\gamma$ production cross-section in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Search for flavour-changing neutral currents in processes with one top quark and a photon using 81 fb${}^{-1}$ of $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS experiment
• Evidence for electroweak production of two jets in association with a $Z\gamma$ pair in $pp$ collisions at $\sqrt{s}=13$ TeV with the ATLAS detector
• Measurements of inclusive and differential cross-sections of combined $t\bar{t}\gamma$ and $tW\gamma$ production in the $e\mu$ channel at 13 TeV with the ATLAS detector
• Search for flavour-changing neutral-current couplings between the top quark and the photon with the ATLAS detector at $\sqrt{s}=13$ TeV
• Triple-real contribution to the quark beam function in QCD at next-to-next-to-next-to-leading order
• Measurement of the jet mass in high transverse momentum $Z(\to b\overline{b})\gamma$ production at $\sqrt{s}=13$ TeV using the ATLAS detector
• Higher-order corrections in $t\bar{t}\gamma$ cross sections
• Observation of Single-Top-Quark Production in Association with a Photon Using the ATLAS Detector
• Measurement of the charge asymmetry in top-quark pair production in association with a photon with the ATLAS experiment
• Climbing to the Top of the ATLAS 13 TeV data
• Measurement of the cross-sections of the electroweak and total production of a $Z\gamma$ pair in association with two jets in $pp$ collisions at $\sqrt{s}$ = 13 TeV with the ATLAS detector
• Top2018: Experimental Summary
• Measurement of the inclusive and differential $\mathrm{t}\overline{\mathrm{t}}\gamma$ cross sections in the single-lepton channel and EFT interpretation at $\sqrt{s}$ = 13 TeV
• Rare top quark production and decays at ATLAS and CMS
• Photon radiation effects in kinematic reconstruction of top quarks
• Reformulation of a likelihood approach to fake-lepton estimation in the framework of Bayesian inference