%0 Journal Article
%T Measurements of top-quark pair to Z-boson cross-section ratios at root s=13, 8, 7 TeV with the ATLAS detector
%A ATLAS Collaboration (Aaboud, M. et al
%A Alvarez Piqueras, D.
%A Barranco Navarro, L.
%A Cabrera Urban, S.
%A Castillo Gimenez, V.
%A Cerda Alberich, L.
%A Costa, M. J.
%A Fernandez Martinez, P.
%A Ferrer, A.
%A Fiorini, L.
%A Fuster, J.
%A Garcia, C.
%A Garcia Navarro, J. E.
%A Gonzalez de la Hoz, S.
%A Higon-Rodriguez, E.
%A Jimenez Pena, J.
%A Lacasta, C.
%A Mamuzic, J.
%A Marti-Garcia, S.
%A Melini, D.
%A Mitsou, V. A.
%A Pedraza Lopez, S.
%A Rodriguez Rodriguez, D.
%A Romero Adam, E.
%A Ros, E.
%A Salt, J.
%A Sanchez Martinez, V.
%A Soldevila, U.
%A Sanchez, J.
%A Valero, A.
%A Valls Ferrer, J. A.
%A Vos, M.
%J Journal of High Energy Physics
%D 2017
%V 02
%N 2
%I Springer
%@ 1029-8479
%G English
%F ATLASCollaborationAaboud_etal2017
%O WOS:000395022700001
%O exported from refbase (https://references.ific.uv.es/refbase/show.php?record=3014), last updated on Fri, 07 Apr 2017 11:30:01 +0000
%X Ratios of top-quark pair to Z-boson cross sections measured from proton-proton-collisions at the LHC centre-of-mass energies of root S = 13 TeV, 8 TeV, and 7 TeV are presented by the ATLAS Collaboration. Single ratios, at a given root S for the two processes and at different root S , for each process, as well as double ratios of the two processes at different root S , are evaluated. The ratios are constructed using previously published ATLAS measurements of the t (t) over bar and Z-boson production cross sections, corrected to a common phase space where required, and a new analysis of Z -> l(+)l(-) where l = e, μat root S = 13 TeV performed with data collected in 2015 with an integrated luminosity of 3.2 fb(-1). Correlations of systematic uncertainties are taken into account when evaluating the uncertainties in the ratios. The correlation model is also used to evaluate the combined cross section of the Z -> e (+) e (-) and the Z -> μ(+) μ(-) channels for each value. The results are compared to calculations performed at next-to-next-to-leading-order accuracy using recent sets of parton distribution functions. The data demonstrate significant power to constrain the gluon distribution function for the Bjorken-x values near 0.1 and the light-quark sea for x < 0.02.
%K Hadron-Hadron scattering (experiments)
%R 10.1007/JHEP02(2017)117
%U http://arxiv.org/abs/1612.03636
%U https://doi.org/10.1007/JHEP02(2017)117
%P 117-54pp