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Author ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Cabrera Urban, S.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Jimenez Pena, J.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M.
Title Measurement of the production cross-section of a single top quark in association with a W boson at 8 TeV with the ATLAS experiment Type Journal Article
Year 2016 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 01 Issue 1 Pages 064 - 48pp
Keywords Hadron-Hadron scattering; Top physics
Abstract (up) The cross-section for the production of a single top quark in association with a W boson in proton-proton collisions at is measured. The dataset corresponds to an integrated luminosity of 20.3 fb(-1), collected by the ATLAS detector in 2012 at the Large Hadron Collider at CERN. Events containing two leptons and one central b-jet are selected. The W t signal is separated from the backgrounds using boosted decision trees, each of which combines a number of discriminating variables into one classifier. Production of W t events is observed with a significance of 7.7 sigma. The cross-section is extracted in a profile likelihood fit to the classifier output distributions. The W t cross-section, inclusive of decay modes, is measured to be 23.0 +/- 1.3(stat.) (-aEuro parts per thousand 3.5) (+ 3.2) (syst.)+/- 1.1(lumi.) pb. The measured cross-section is used to extract a value for the CKM matrix element |V (tb) | of 1.01 +/- 0.10 and a lower limit of 0.80 at the 95% confidence level. The cross-section for the production of a top quark and a W boson is also measured in a fiducial acceptance requiring two leptons with p (T) > 25 GeV and |eta| < 2.5, one jet with p (T) > 20 GeV and |eta| < 2.5, and E (T) (miss) > 20 GeV, including both W t and top-quark pair events as signal. The measured value of the fiducial cross-section is 0.85 +/- A 0.01(stat.) (-aEuro parts per thousand 0.07) (+ 0.07) (syst.)+/- 0.03(lumi.) pb.
Address [Jackson, P.; Lee, L.; Petridis, A.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000368174800001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2523
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Author ATLAS Collaboration (Aaboud, M. et al); Alvarez Piqueras, D.; Barranco Navarro, L.; Cabrera Urban, S.; Castillo Gimenez, V.; Cerda Alberich, L.; Costa, M.J.; Escobar, C.; Estrada Pastor, O.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Higon-Rodriguez, E.; Jimenez Pena, J.; Lacasta, C.; Madaffari, D.; Mamuzic, J.; Marti-Garcia, S.; Melini, D.; Mitsou, V.A.; Pedraza Lopez, S.; Rodriguez Bosca, S.; Rodriguez Rodriguez, D.; Romero Adam, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M.
Title Analysis of the Wtb vertex from the measurement of triple-differential angular decay rates of single top quarks produced in the t-channel at root s=8 TeV with the ATLAS detector Type Journal Article
Year 2017 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 12 Issue 12 Pages 017 - 60pp
Keywords Electroweak interaction; Hadron-Hadron scattering (experiments); Top physics
Abstract (up) The electroweak production and subsequent decay of single top quarks in the t-channel is determined by the properties of the Wtb vertex, which can be described by the complex parameters of an effective Lagrangian. An analysis of a triple-differential decay rate in t-channel production is used to simultaneously determine five generalised helicity fractions and phases, as well as the polarisation of the produced top quark. The complex parameters are then constrained. This analysis is based on 20.2 fb(-1) of proton-proton collision data at a centre-of-mass energy of 8 TeV collected with the ATLAS detector at the LHC. The fraction of decays containing transversely polarised W bosons is measured to be f(1) = 0.30 +/- 0.05. The phase between amplitudes for transversely and longitudinally polarised W bosons recoiling against left-handed b-quarks is measured to be delta = 0.002 pi(+0.016 pi)(+0.017 pi), giving no indication of CP violation. The fractions of longitudinal or transverse W bosons accompanied by right-handed b-quarks are also constrained. Based on these measurements, limits are placed at 95% CL on the ratio of the complex coupling parameters Re [g(R)/V-L is an element of [-0.12, 0.17] and Im [g(R)/V-L is an element of [-0.07, 0.06]. Constraints are also placed on the ratios vertical bar V-R/V-L vertical bar and vertical bar g(L)/V-L vertical bar. In addition, the polarisation of single top quarks in the t-channel is constrained to be P > 0.72 (95% CL). None of the above measurements make assumptions about the value of any of the other parameters or couplings and all of them are in agreement with the Standard Model.
Address [Jackson, P.; Petridis, A.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia, Email: atlas.publications@cern.ch
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000417756900002 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 3417
Permanent link to this record
 

 
Author ATLAS Collaboration (Aad, G. et al); Amos, K.R.; Aparisi Pozo, J.A.; Bailey, A.J.; Cabrera Urban, S.; Cantero, J.; Cardillo, F.; Castillo Gimenez, V.; Chitishvili, M.; Costa, M.J.; Didenko,, M.; Escobar, C.; Fiorini, L.; Fullana Torregrosa, E.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gomez Delegido, A.J.; Gonzalez de la Hoz, S.; Gonzalvo Rodriguez, G.R.; Guerrero Rojas, J.G.R.; Higon-Rodriguez, E.; Lacasta, C.; Lozano Bahilo, J.J.; Marti-Garcia, S.; Martinez Agullo, P.; Miralles Lopez, M.; Mitsou, V.A.; Monsonis Romero, L.; Moreno Llacer, M.; Munoz Perez, D.; Navarro-Gonzalez, J.; Poveda, J.; Prades Ibañez, A.; Rubio Jimenez, A.; Ruiz-Martinez, A.; Sabatini, P.; Salt, J.; Sanchez Sebastian, V.; Sayago Galvan, I.; Senthilkumar, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valls Ferrer, J.A.; Varriale, L.; Villaplana Perez, M.; Vos, M.
Title Measurement of the t(t)over-bar production cross-section in pp collisions at root s=5.02 TeV with the ATLAS detector Type Journal Article
Year 2023 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 06 Issue 6 Pages 138 - 54pp
Keywords Hadron-Hadron Scattering; Top Physics
Abstract (up) The inclusive top-quark pair ( t (t) over bar) production cross-section sigma(t (t) over bar) is measured in proton-proton collisions at a centre-of-mass energy root s = 5.02TeV, using 257 pb(-1) of data collected in 2017 by the ATLAS experiment at the LHC. The t (t) over bar cross-section is measured in both the dilepton and single-lepton final states of the t<overline> t system and then combined. The combination of the two measurements yields sigma(t (t) over bar) = 67.5 +/- 0.9 (stat.) +/- 2.3 (syst.) +/- 1.1 (lumi.) +/- 0.2 (beam) pb, where the four uncertainties reflect the limited size of the data sample, experimental and theoretical systematic effects, and imperfect knowledge of both the integrated luminosity and the LHC beam energy, giving a total uncertainty of 3.9%. The result is in agreement with theoretical quantum chromodynamic calculations at next-to-next-to-leading order in the strong coupling constant, including the resummation of next-to-next-to-leading logarithmic soft-gluon terms, and constrains the parton distribution functions of the proton at large Bjorken-x.
Address [Filmer, E. K.; Jackson, P.; Kong, A. X. Y.; Potti, H.; Ruggeri, T. A.; Ting, E. X. L.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:001035251000001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 5638
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Author ATLAS Collaboration (Aad, G. et al); Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Jimenez Pena, J.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Moles-Valls, R.; Oliver Garcia, E.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Torro Pastor, E.; Valero, A.; Valladolid Gallego, E.; Valls Ferrer, J.A.; Vos, M.
Title Determination of the top-quark pole mass using t(t)over-bar+1-jet events collected with the ATLAS experiment in 7 TeV pp collisions Type Journal Article
Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 10 Issue 10 Pages 121 - 41pp
Keywords Hadron-Hadron Scattering; Top physics
Abstract (up) The normalized differential cross section for top-quark pair production in association with at least one jet is studied as a function of the inverse of the invariant mass of the t (t) over bar + 1-jet system. This distribution can be used for a precise determination of the top-quark mass since gluon radiation depends on the mass of the quarks. The experimental analysis is based on proton-proton collision data collected by the ATLAS detector at the LHC with a centre-of-mass energy of 7TeV corresponding to an integrated luminosity of 4.6 fb(-1). The selected events were identified using the lepton+jets top-quark-pair decay channel, where lepton refers to either an electron or a muon. The observed distribution is compared to a theoretical prediction at next-to-leading-order accuracy in quantum chromodynamics using the pole-mass scheme. With this method, the measured value of the top-quark pole mass, m(t)(pole), is: m(t)(pole) t = 173.7 +/- 1.5 (stat.) +/- 1.4 (syst.)(-0.5)(+1.0) (theory) GeV. This result represents the most precise measurement of the top-quark pole mass to date.
Address [Jackson, P.; Lee, L.; Soni, N.; White, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000363476900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2434
Permanent link to this record
 

 
Author ATLAS Collaboration (Aad, G. et al); Alvarez Piqueras, D.; Cabrera Urban, S.; Castillo Gimenez, V.; Costa, M.J.; Fernandez Martinez, P.; Ferrer, A.; Fiorini, L.; Fuster, J.; Garcia, C.; Garcia Navarro, J.E.; Gonzalez de la Hoz, S.; Hernandez Jimenez, Y.; Higon-Rodriguez, E.; Irles Quiles, A.; Jimenez Pena, J.; Kaci, M.; King, M.; Lacasta, C.; Lacuesta, V.R.; Marti-Garcia, S.; Mitsou, V.A.; Pedraza Lopez, S.; Perez Garcia-Estañ, M.T.; Romero Adam, E.; Ros, E.; Salt, J.; Sanchez Martinez, V.; Soldevila, U.; Sanchez, J.; Valero, A.; Valls Ferrer, J.A.; Vos, M.
Title Measurement of the t(t)over-barW and t(t)over-barZ production cross sections in pp collisions at root s=8 TeV with the ATLAS detector Type Journal Article
Year 2015 Publication Journal of High Energy Physics Abbreviated Journal J. High Energy Phys.
Volume 11 Issue 11 Pages 172 - 48pp
Keywords Electroweak interaction; Hadron-Hadron scattering; Top physics
Abstract (up) The production cross sections of top-quark pairs in association with massive vector bosons have been measured using data from pp collisions at root s = 8 TeV. The dataset corresponds to an integrated luminosity of 20.3 fb(-1) collected by the ATLAS detector in 2012 at the LHC. Final states with two, three or four leptons are considered. A fit to the data considering the t (t) over barW and t (t) over barZ processes simultaneously yields a significance of 5.0 sigma (4.2 sigma) over the background-only hypothesis for t (t) over barW (t (t) over barZ) production. The measured cross sections are sigma(t (t) over barW) = 369(-91)(+100) fb and sigma(t (t) over barZ) = 176(-52)(+58) fb. The background-only hypothesis with neither t (t) over barW nor t (t) over barZ production is excluded at 7.1 sigma. All measurements are consistent with next-to-leading-order calculations for the t (t) over barW and t (t) over barZ processes.
Address [Jackson, P.; Lee, L.; Petridis, A.; Soni, N.; Whitel, M. J.] Univ Adelaide, Dept Phys, Adelaide, SA, Australia
Corporate Author Thesis
Publisher Springer Place of Publication Editor
Language English Summary Language Original Title
Series Editor Series Title Abbreviated Series Title
Series Volume Series Issue Edition
ISSN 1029-8479 ISBN Medium
Area Expedition Conference
Notes WOS:000366139900001 Approved no
Is ISI yes International Collaboration yes
Call Number IFIC @ pastor @ Serial 2488
Permanent link to this record