Differential Top-Antitop Cross-Section Measurements as a Function of Observables Constructed from Final-State Particles Using pp Collisions at √s̅ = 7 TeV in the ATLAS Detector
Date
ORCID
Journal Title
Journal ISSN
Volume Title
Publisher
item.page.doi
Abstract
Various differential cross-sections are measured in top-quark pair tt̅ events produced in proton-proton collisions at a centre-of-mass energy of √s̅ = 7 TeV at the LHC with the ATLAS detector. These differential cross-sections are presented in a data set corresponding to an integrated luminosity of 4.6 fb⁻¹. The differential cross-sections are presented in terms of kinematic variables, such as momentum, rapidity and invariant mass, of a top-quark proxy referred to as the pseudo-top-quark as well as the pseudo-top-quark pair system. The dependence of the measurement on theoretical models is minimal.
The measurements are performed on tt̅ events in the lepton+jets channel, requiring exactly one charged lepton and at least four jets with at least two of them tagged as originating from a b-quark. The hadronic and leptonic pseudo-top-quarks are defined via the leptonic or hadronic decay mode of the W boson produced by the top-quark decay in events with a single charged lepton. Differential cross-section measurements of the pseudo-top-quark variables are compared with several Monte Carlo models that implement next-to-leading order or leading-order multi-leg matrix-element calculations.