Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (Zt tˉZ) 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 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 σ ttˉ=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 ttˉZ 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 χ /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
Farina E. M.;Introzzi G.;Livan M.;Negri A.;Pezzotti L.;Rebuzzi D. M.;Rimoldi A.;Rovelli G.;Sottocornola S.;
2021-01-01
Abstract
Measurements of both the inclusive and differential production cross sections of a top-quark–antiquark pair in association with a Z boson (Zt tˉZ) 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 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 σ ttˉ=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 ttˉZ 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 χ /ndf and p value computation. Overall, good agreement is observed between the unfolded data and the predictions.I documenti in IRIS sono protetti da copyright e tutti i diritti sono riservati, salvo diversa indicazione.
