Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on √s=13 TeV proton–proton collision data with an integrated luminosity of 139 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 σtt¯Z=0.99±0.05 (stat.) ±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 tt¯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 χ2/ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.
Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at √s=13 TeV with the ATLAS detector / De Castro , S. ; Fabbri , L. ; Gabrielli , A. ; Rinaldi , L. ; Semprini Cesari , N. ; Sioli , M. ; Villa , M. ; Zoccoli , A. ; Bellagamba , L. ; Boscherini , D. ; Bruni , A. ; Bruni , G. ; Giacobbe , B. ; Polini , A. ; Sbarra , C. ; Sidoti , A. ; Franchini , M. ; Romano , M. ; Valentinetti , S. ; Alberghi , G. L. ; Lasagni Manghi , F; Massa , L. ; Vittori , C. ; Alfonsi , F: ; Cabras , G. ; Cervelli , A. ; Negrini , M. ; Todome , K. ; Carratta , G. ; Cavalli , N. ; Clissa , L. ; ATLAS collaboration. - In: THE EUROPEAN PHYSICAL JOURNAL. C, PARTICLES AND FIELDS. - ISSN 1434-6044. - STAMPA. - 81:8(2021), pp. 737.1-737.43. [10.1140/epjc/s10052-021-09439-4]
Measurements of the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson at √s=13 TeV with the ATLAS detector
De Castro , S.;Fabbri , L.;Gabrielli , A.;Rinaldi , L.;Semprini Cesari , N.;Sioli , M.;Villa , M.;Zoccoli , A.;Bellagamba , L.;Boscherini , D.;Bruni , A.;Giacobbe , B.;Polini , A.;Sbarra , C.;Franchini , M.;Romano , M.;Valentinetti , S.;Alberghi , G. L.;Lasagni Manghi , F;Massa , L.;Vittori , C.;Cabras , G.;Todome , K.;Carratta , G.;Cavalli , N.;Clissa , L.;
2021
Abstract
Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (tt¯Z) are presented. The measurements are performed by targeting final states with three or four isolated leptons (electrons or muons) and are based on √s=13 TeV proton–proton collision data with an integrated luminosity of 139 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 σtt¯Z=0.99±0.05 (stat.) ±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 tt¯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 χ2/ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.File | Dimensione | Formato | |
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