Measurements of top-quark pair differential cross-sections in the lepton+jets channel in pp collisions at √s=8TeV using the ATLAS detector

Aad, G. and Abbott, B. and Abdallah, J. and Abdinov, O. and Aben, R. and Krasznahorkay, Attila and Nagai, Yoshikazu and Pásztor, Gabriella and Tóth, József (2016) Measurements of top-quark pair differential cross-sections in the lepton+jets channel in pp collisions at √s=8TeV using the ATLAS detector. EUROPEAN PHYSICAL JOURNAL C, 76 (10). ISSN 1434-6044

Preview

Text 1511.04716.pdf Available under License Creative Commons Attribution. Download (1MB) | Preview

Abstract

Measurements of normalized differential cross-sections of top-quark pair production are presented as a function of the top-quark, t¯t system and event-level kinematic observables in proton–proton collisions at a centre-of-mass energy of √s = 8 TeV. The observables have been chosen to emphasize the t¯t production process and to be sensitive to effects of initial- and final-state radiation, to the different parton distribution functions, and to non-resonant processes and higher-order corrections. The dataset corresponds to an integrated luminosity of 20.3 fb−1, recorded in 2012 with the ATLAS detector at the CERN Large Hadron Collider. Events are selected in the lepton+jets channel, requiring exactly one charged lepton and at least four jets with at least two of the jets tagged as originating from a b-quark. The measured spectra are corrected for detector effects and are compared to several Monte Carlo simula- tions. The results are in fair agreement with the predictions over a wide kinematic range. Nevertheless, most generators predict a harder top-quark transverse momentum distribution at high values than what is observed in the data. Predictions beyond NLO accuracy improve the agreement with data at high top-quark transverse momenta. Using the current settings and parton distribution functions, the rapidity distributions are not well modelled by any gen- erator under consideration. However, the level of agreement is improved when more recent sets of parton distribution functions are used.

Actions (login required)

Edit Item