300 research outputs found
Measurement of the Wt Production Cross Section in Dilepton Events with the ATLAS Detector
No full textSingle top quark production, accounting for of the overall top quark production at the LHC, constitutes an excellent probe of the 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 boson. The close similarity of its final state to that of top quark pair production, which has a more than times larger production cross-section, makes the measurement a challenging endeavour. Hence multivariate techniques are appropriate to identify the signal. The results of the latest cross-section measurement with the ATLAS detector, based on of -collision data at , are presented
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
Single Top Quark Production at ATLAS
No full textRecent ATLAS analyses of single top-quark production at are discussed
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
Measurement of Charm and Beauty Dijet Photoproduction Cross Sections using Secondary Vertexing at ZEUS
No full textEvidence 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
Search for high-mass dilepton resonances in pp collisions at root s=8 TeV with the ATLAS detector
No full textSee paper for full list of authors - 14 pages plus author list + cover page (31 pages total), 5 figures, 4 tables, submitted to Physical Review D, All figures including auxiliary figures are available at http://atlas.web.cern.ch/Atlas/GROUPS/PHYSICS/PAPERS/EXOT-2012-19/International audienceThis article describes a search for high-mass resonances decaying to a pair of photons using a sample of fb of collisions at TeV recorded with the ATLAS detector at the Large Hadron Collider. The data are found to be in agreement with the Standard Model prediction, and limits are reported in the framework of the Randall-Sundrum model. This theory leads to the prediction of graviton states, the lightest of which could be observed at the Large Hadron Collider. A lower limit of () TeV at 95% confidence level is set on the mass of the lightest graviton for couplings of ()
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