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 - The ATLAS collaboration
AU - Aaboud, M.
AU - Aad, G.
AU - Abbott, B.
AU - Abdallah, J.
AU - Abdinov, O.
AU - Abeloos, B.
AU - Abidi, S. H.
AU - AbouZeid, O. S.
AU - Abraham, N. L.
AU - Abramowicz, H.
AU - Abreu, H.
AU - Abreu, R.
AU - Abulaiti, Y.
AU - Acharya, B. S.
AU - Adachi, S.
AU - Adamczyk, L.
AU - Adams, D. L.
AU - Adelman, J.
AU - Adye, T.
AU - Affolder, A. A.
AU - Agatonovic-Jovin, T.
AU - Agheorghiesei, C.
AU - Aguilar-Saavedra, J. A.
AU - Ahlen, S. P.
AU - Ahmadov, F.
AU - Aielli, G.
AU - Akatsuka, S.
AU - Akerstedt, H.
AU - Åkesson, T. P.A.
AU - Akimov, A. V.
AU - Alberghi, G. L.
AU - Albert, J.
AU - Alconada Verzini, M. J.
AU - Aleksa, M.
AU - Aleksandrov, I. N.
AU - Alexa, C.
AU - Alexander, G.
AU - Alexopoulos, T.
AU - Alhroob, M.
AU - Ali, B.
AU - Aliev, M.
AU - Alimonti, G.
AU - Alison, J.
AU - Arnold, H.
AU - Da Via, C.
AU - Dao, V.
AU - Hobbs, J.
AU - Jia, J.
AU - Piacquadio, G.
AU - Tsybychev, D.
N1 - Publisher Copyright:
© 2017, The Author(s).
PY - 2017/2/1
Y1 - 2017/2/1
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.]
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.]
KW - Hadron-Hadron scattering (experiments)
UR - https://www.scopus.com/pages/publications/85016562530
U2 - 10.1007/JHEP02(2017)117
DO - 10.1007/JHEP02(2017)117
M3 - Article
AN - SCOPUS:85016562530
SN - 1126-6708
VL - 2017
JO - Journal of High Energy Physics
JF - Journal of High Energy Physics
IS - 2
M1 - 117
ER -