TY - JOUR
T1 - Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
AU - Aaboud, M
AU - Aad, G
AU - Abbott, B.
AU - Abdallah, J
AU - Abdinov, O
AU - Abeloos, B
AU - Åkesson, Torsten
AU - Bocchetta, Simona
AU - BRYNGEMARK, LENE
AU - Doglioni, Caterina
AU - Hedberg, Vincent
AU - Jarlskog, Göran
AU - Kalderon, Charles
AU - Lytken, Else
AU - Mjörnmark, Ulf
AU - Smirnova, Oxana
AU - Viazlo, Oleksandr
AU - ATLAS Collaboration
N1 - Export Date: 13 June 2017
PY - 2017
Y1 - 2017
N2 - Ratios of top-quark pair to Z-boson cross sections measured from proton-proton collisions at the LHC centre-of-mass energies of s=13 TeV, 8 TeV, and 7 TeV are presented by the ATLAS Collaboration. Single ratios, at a given s for the two processes and at different s for each process, as well as double ratios of the two processes at different s, are evaluated. The ratios are constructed using previously published ATLAS measurements of the tt¯ 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, μ at 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 s 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.[Figure not available: see fulltext.] © 2017, The Author(s).
AB - Ratios of top-quark pair to Z-boson cross sections measured from proton-proton collisions at the LHC centre-of-mass energies of s=13 TeV, 8 TeV, and 7 TeV are presented by the ATLAS Collaboration. Single ratios, at a given s for the two processes and at different s for each process, as well as double ratios of the two processes at different s, are evaluated. The ratios are constructed using previously published ATLAS measurements of the tt¯ 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, μ at 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 s 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.[Figure not available: see fulltext.] © 2017, The Author(s).
KW - Hadron-Hadron scattering (experiments)
U2 - 10.1007/JHEP02(2017)117
DO - 10.1007/JHEP02(2017)117
M3 - Article
SN - 1029-8479
VL - 2017
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 2
M1 - 117
ER -