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



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.


Supplementary material is available at the publisher's website (http://dx.doi.org/10.1007/JHEP06(2015)100).


Hadron-hadron scattering, Quarks, Partons, Hadron colliders, Monte Carlo method, Resummation, Leptons (Nuclear physics, Jets (Nuclear physics), Proton-proton interactions, W bosons



CC BY 4.0 (Attribution), ©2015 The Authors