62 research outputs found
Measurements of Single Top-Quark Production Using the ATLAS Detector at the LHC
No full textRecent measurements of the production of single top quarks in proton-proton collisions at a centre-of-mass energy of are presented. The analysed data with an integrated luminosity of was recorded using the ATLAS detector at the LHC. Differential cross sections for production were measured, an analysis of the quantum interference between and production was performed, and evidence for production was found. The results were compared with state-of-the-art theoretical calculations, and no significant deviations from the Standard Model expectations was observed
Single Top-Quark Production Cross Section Using the ATLAS Detector at the LHC
No full textRecent measurements of the production of single top quarks in proton--proton collisions at centre-of-mass energies of , and with the ATLAS detector at the LHC are presented. Four measurements of the production cross sections for single top quarks via the - and -channel exchange of a boson as well as in association with a \Wboson{} are discussed. The results are compared to state-of-the-art theoretical calculations, and used to extract the value of the CKM matrix element . Recently found evidence for the production of single top quarks in the -channel at is presented. Finally, the determination of anomalous couplings at the vertex from an analysis of top-quark decays is shown
Measurement of the Wt Production Cross-Section in Dilepton Events with the ATLAS Detector
No full textAbstractSingle top-quark production, accounting for ∼1/3 of the overall top-quark production at the LHC, constitutes an excellent probe of the W-t-b coupling, which is sensitive to certain types of new physics. One important production mode in the Standard Model is the creation of a single top quark in association with a W boson. The close similarity of its final state to that of top-quark pair production, which has a more than 10 times larger production cross-section, makes the measurement a challenging endeavour. Hence multivariate techniques are appropriate to identify the Wt signal. The results of the latest Wt cross-section measurement with the ATLAS detector, based on 20 fb−1 of pp-collision data at s=8 TeV, are presented
Measurement of the Associated Production of a Single Top Quark and a W Boson in Single-Lepton Events with the ATLAS Detector
No full textThe production of a single top quark in association with a W boson (Wt) is measured with the ATLAS detector using proton-proton collision events with one lepton, three jets and missing transverse energy at √s = 8 TeV. Signal events are identified using an artificial neural network in an unconventional manner, addressing the large uncertainties due to the major background, which has an about 10 times larger cross section and a very similar signature compared with the Wt signal. State-of-the-art statistical methods are used to validate the modelling of the signal and the background, and to extract the cross section for Wt production. The cross section is found to be consistent with related measurements as well as the Standard Model prediction. In addition, a direct measurement of the CKM matrix element Vtb is performed
Single Top Quark Production at ATLAS
No full textRecent ATLAS analyses of single top-quark production at are discussed
Combined inclusive diffractive cross sections measured with forward proton spectrometers in deep inelastic ep scattering at HERA
No full textA combination of the inclusive diffractive cross section measurements made by the H1 and ZEUS Collaborations at HERA is presented. The analysis uses samples of diffractive deep inelastic ep scattering data at a centre-of-mass energy √s= 318 Gev where leading protons are detected by dedicated spectrometers. Correlations of systematic uncertainties are taken into account, resulting in an improved precision of the cross section measurement which reaches 6 % for the most precise points. The combined data cover the range 2.5 < Q 2 < 200 GeV 2 in photon virtuality, 0.00035 < xP < 0.09 in proton fractional momentum loss, 0.09 <{pipe}t{pipe}< 0.55 GeV 2 in squared four-momentum transfer at the proton vertex and 0.0018 < β <0.816 in β=x/xP, where x is the Bjorken scaling variable. © 2012 The Author(s).0H1 and ZEUS CollaborationsSCOPUS: ar.jinfo:eu-repo/semantics/publishe
Search for heavy diboson resonances in semileptonic final states in pp collisions at s=13 TeV with the ATLAS detector
No full textThis article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article’s Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article’s Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder. To view a copy of this licence, visit http://creativecommons.org/licenses/by/4.0/
Evidence for Electroweak Production of W(+/-)W(+/-)jj in pp Collisions at root s=8 TeV with the ATLAS Detector
No full textFurther distribution of this work must maintain attribution to the author(s) and the published article's title, journal citation, and DOI.This Letter presents the first study of W±W±jj, same-electric-charge diboson production in association with two jets, using 20.3 fb-1 of proton-proton collision data at √s=8 TeV recorded by the ATLAS detector at the Large Hadron Collider. Events with two reconstructed same-charge leptons (e±e±, e±μ±, and μ±μ±) and two or more jets are analyzed. Production cross sections are measured in two fiducial regions, with different sensitivities to the electroweak and strong production mechanisms. First evidence for W±W±jj production and electroweak-only W±W±jj production is observed with a significance of 4.5 and 3.6 standard deviations, respectively. The measured production cross sections are in agreement with standard model predictions. Limits at 95% confidence level are set on anomalous quartic gauge couplings
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