scholarly journals Measurements of top-quark pair differential and double-differential cross-sections in the $$\ell $$+jets channel with pp collisions at $$\sqrt{s}=13$$ TeV using the ATLAS detector

2019 ◽  
Vol 79 (12) ◽  
Author(s):  
G. Aad ◽  
◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
Top Quark ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Double Differential Cross Section ◽  
Quark Pairs ◽  
Top Quark Production ◽  
Using Data

AbstractSingle- and double-differential cross-section measurements are presented for the production of top-quark pairs, in the lepton + jets channel at particle and parton level. Two topologies, resolved and boosted, are considered and the results are presented as a function of several kinematic variables characterising the top and $$t\bar{t}$$ t t ¯ system and jet multiplicities. The study was performed using data from pp collisions at centre-of-mass energy of 13 TeV collected in 2015 and 2016 by the ATLAS detector at the CERN Large Hadron Collider (LHC), corresponding to an integrated luminosity of $$36~\mathrm {fb}^{-1}$$ 36 fb - 1 . Due to the large $$t\bar{t}$$ t t ¯ cross-section at the LHC, such measurements allow a detailed study of the properties of top-quark production and decay, enabling precision tests of several Monte Carlo generators and fixed-order Standard Model predictions. Overall, there is good agreement between the theoretical predictions and the data.

scholarly journals Measurements of top-quark pair spin correlations in the $$e\mu $$ channel at $$\sqrt{s} = 13$$ TeV using pp collisions in the ATLAS detector

2020 ◽  
Vol 80 (8) ◽  
Author(s):  
M. Aaboud ◽  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
...  
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Top Quark ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Absolute Difference ◽  
Opening Angle ◽  
Differential Cross Sections ◽  
Spin Correlations ◽  
Fixed Order

Abstract A measurement of observables sensitive to spin correlations in $$t\bar{t}$$tt¯ production is presented, using 36.1 $$\hbox {fb}^{-1}$$fb-1 of pp collision data at $$\sqrt{s} = 13$$s=13 TeV recorded with the ATLAS detector at the Large Hadron Collider. Differential cross-sections are measured in events with exactly one electron and one muon with opposite-sign electric charge as a function of the azimuthal opening angle and the absolute difference in pseudorapidity between the electron and muon candidates in the laboratory frame. The azimuthal opening angle is also measured as a function of the invariant mass of the $$t\bar{t}$$tt¯ system. The measured differential cross-sections are compared to predictions by several NLO Monte Carlo generators and fixed-order calculations. The observed degree of spin correlation is somewhat higher than predicted by the generators used. The data are consistent with the prediction of one of the fixed-order calculations at NLO, but agree less well with higher-order predictions. Using these leptonic observables, a search is performed for pair production of supersymmetric top squarks decaying into Standard Model top quarks and light neutralinos. Top squark masses between 170 and 230 GeV are largely excluded at the 95% confidence level for kinematically allowed values of the neutralino mass.

scholarly journals Measurement of fiducial and differential $$W^+W^-$$ production cross-sections at $$\sqrt{s}=13$$ TeV with the ATLAS detector

2019 ◽  
Vol 79 (10) ◽  
Author(s):  
M. Aaboud ◽  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
...  
Keyword(s):  
Transverse Momentum ◽  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Hadron Collider ◽  
Effective Field ◽  
Electroweak Gauge Boson ◽  
Using Data ◽  
Background Events

Abstract A measurement of fiducial and differential cross-sections for $$W^+W^-$$W+W- production in proton–proton collisions at $$\sqrt{s}=13$$s=13 TeV with the ATLAS experiment at the Large Hadron Collider using data corresponding to an integrated luminosity of 36.1 $$\hbox {fb}^{-1}$$fb-1 is presented. Events with one electron and one muon are selected, corresponding to the decay of the diboson system as $$WW\rightarrow e^{\pm }\nu \mu ^{\mp }\nu $$WW→e±νμ∓ν. To suppress top-quark background, events containing jets with a transverse momentum exceeding 35 GeV are not included in the measurement phase space. The fiducial cross-section, six differential distributions and the cross-section as a function of the jet-veto transverse momentum threshold are measured and compared with several theoretical predictions. Constraints on anomalous electroweak gauge boson self-interactions are also presented in the framework of a dimension-six effective field theory.

scholarly journals Measurement of single top-quark production in association with a W boson in the single-lepton channel at $$\sqrt{s} = 8\,\text {TeV}$$ with the ATLAS detector

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
K. Abeling ◽  
...  
Keyword(s):  
Neural Network ◽  
Cross Section ◽  
Top Quark ◽  
W Boson ◽  
Production Cross ◽  
Hadron Collider ◽  
Atlas Detector ◽  
Proton Proton ◽  
Top Quark Production ◽  
Quark Production

AbstractThe production cross-section of a top quark in association with a W boson is measured using proton–proton collisions at $$\sqrt{s} = 8\,\text {TeV}$$ s = 8 TeV . The dataset corresponds to an integrated luminosity of $$20.2\,\text {fb}^{-1}$$ 20.2 fb - 1 , and was collected in 2012 by the ATLAS detector at the Large Hadron Collider at CERN. The analysis is performed in the single-lepton channel. Events are selected by requiring one isolated lepton (electron or muon) and at least three jets. A neural network is trained to separate the tW signal from the dominant $$t{\bar{t}}$$ t t ¯ background. The cross-section is extracted from a binned profile maximum-likelihood fit to a two-dimensional discriminant built from the neural-network output and the invariant mass of the hadronically decaying W boson. The measured cross-section is $$\sigma _{tW} = 26 \pm 7\,\text {pb}$$ σ tW = 26 ± 7 pb , in good agreement with the Standard Model expectation.

scholarly journals Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at $$\sqrt{s} = 13$$ TeV with the ATLAS detector

2021 ◽  
Vol 81 (8) ◽  
Author(s):  
◽  
G. Aad ◽  
B. Abbott ◽  
D. C. Abbott ◽  
A. Abed Abud ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Top Quark ◽  
Production Cross ◽  
Hadron Collider ◽  
Inclusive Cross Section ◽  
Atlas Detector ◽  
Proton Collision ◽  
Proton Proton ◽  
Theoretical Predictions

AbstractMeasurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson ($$t{\bar{t}}Z$$ t t ¯ Z ) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on $$\sqrt{s} = 13$$ s = 13  TeV proton–proton collision data with an integrated luminosity of 139 $$\hbox {fb}^{-1}$$ fb - 1 , recorded from 2015 to 2018 with the ATLAS detector at the CERN Large Hadron Collider. The inclusive cross section is measured to be $$\sigma _{t{\bar{t}}Z} = 0.99 \pm 0.05$$ σ t t ¯ Z = 0.99 ± 0.05  (stat.) $$\pm \, 0.08$$ ± 0.08  (syst.) pb, in agreement with the most precise theoretical predictions. The differential measurements are presented as a function of a number of kinematic variables which probe the kinematics of the $$t{\bar{t}}Z$$ t t ¯ Z system. Both absolute and normalised differential cross-section measurements are performed at particle and parton levels for specific fiducial volumes and are compared with theoretical predictions at different levels of precision, based on a $$\chi ^{2}/$$ χ 2 / ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.

scholarly journals Erratum to: Measurement of differential cross sections and W+/W− cross-section ratios for W boson production in association with jets at $$ \sqrt{s} $$ = 8 TeV with the ATLAS detector

2020 ◽  
Vol 2020 (10) ◽  
Author(s):  
M. Aaboud ◽  
◽  
G. Aad ◽  
B. Abbott ◽  
O. Abdinov ◽  
...  
Keyword(s):  
Cross Section ◽  
Cross Sections ◽  
Differential Cross ◽  
W Boson ◽  
Atlas Detector ◽  
Boson Production ◽  
Differential Cross Sections ◽  
8 Tev ◽  
W Boson Production

Two additions impacting tables 3 and 4 in ref. [1] are presented in the following. No significant impact is found for other results or figures in ref. [1].

scholarly journals Resummed Differential Cross Sections for Top-Quark Pairs at the LHC

2016 ◽  
Vol 116 (20) ◽  
Author(s):  
Benjamin D. Pecjak ◽  
Darren J. Scott ◽  
Xing Wang ◽  
Li Lin Yang
Keyword(s):  
Cross Sections ◽  
Differential Cross ◽  
Top Quark ◽  
Differential Cross Sections ◽  
Quark Pairs ◽  
Top Quark Pairs

scholarly journals Top quark studies with the ATLAS detector

2015 ◽  
Vol 39 ◽  
pp. 1560092
Author(s):  
Marcella Capua
Keyword(s):  
Pair Production ◽  
Cross Sections ◽  
Top Quark ◽  
W Boson ◽  
Production Cross ◽  
Charge Asymmetry ◽  
Atlas Detector ◽  
Top Quark Production ◽  
Top Pair Production ◽  
8 Tev

The latest top quark studies in proton-proton collisions at a centre-of-mass energy of 7 and 8 TeV with the ATLAS detector are reported. We present recent results on the top pair production inclusive cross-sections, top pair production differential cross-section in the resolved and boosted regimes, single top-quark production cross-sections measured in the t-channel, s-channel and W-boson associated processes, as well as the determination of the CKM matrix element [Formula: see text]. The results are compared with theoretical expectations. Latest ATLAS results on top properties will be also shown in terms of direct and pole mass, spin correlations and charge asymmetry.

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