Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector

Detalhes bibliográficos
Autor(a) principal: Santos, S. P. Amor dos
Data de Publicação: 2017
Outros Autores: Carvalho, J., Fiolhais, M. C. N., Galhardo, B., Veloso, F., Wolters, H., ATLAS Collaboration
Tipo de documento: Artigo
Idioma: eng
Título da fonte: Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)
Texto Completo: http://hdl.handle.net/10316/108247
https://doi.org/10.1007/JHEP02(2017)117
Resumo: 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.
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spelling Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detectorHadron-Hadron scattering (experiments)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.We thank CERN for the very successful operation of the LHC, as well as the support sta from our institutions without whom ATLAS could not be operated e ciently. We acknowledge the support of ANPCyT, Argentina; YerPHI, Armenia; ARC, Australia; BMWFW and FWF, Austria; ANAS, Azerbaijan; SSTC, Belarus; CNPq and FAPESP, Brazil; NSERC, NRC and CFI, Canada; CERN; CONICYT, Chile; CAS, MOST and NSFC, China; COLCIENCIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF, I-CORE and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; FOM and NWO, Netherlands; RCN, Norway; MNiSW and NCN, Poland; FCT, Portugal; MNE/IFA, Romania; MES of Russia and NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZ S, Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TAEK, Turkey; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, the Canada Council, CANARIE, CRC, Compute Canada, FQRNT, and the Ontario Innovation Trust, Canada; EPLANET, ERC, FP7, Horizon 2020 and Marie Sk lodowska-Curie Actions, European Union; Investissements d'Avenir Labex and Idex, ANR, R egion Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co- nanced by EU-ESF and the Greek NSRF; BSF, GIF and Minerva, Israel; BRF, Norway; Generalitat de Catalunya, Generalitat Valenciana, Spain; the Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, the ATLAS Tier-1 facilities at TRIUMF (Canada), NDGF (Denmark, Norway, Sweden), CC-IN2P3 (France), KIT/GridKA (Germany), INFN-CNAF (Italy), NL-T1 (Netherlands), PIC (Spain), ASGC (Taiwan), RAL (U.K.) and BNL (U.S.A.), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in ref. [80].Springer Nature2017info:eu-repo/semantics/publishedVersioninfo:eu-repo/semantics/articlehttp://hdl.handle.net/10316/108247http://hdl.handle.net/10316/108247https://doi.org/10.1007/JHEP02(2017)117engSantos, S. P. Amor dosCarvalho, J.Fiolhais, M. C. N.Galhardo, B.Veloso, F.Wolters, H.ATLAS Collaborationinfo:eu-repo/semantics/openAccessreponame:Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos)instname:Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãoinstacron:RCAAP2023-08-21T09:27:18Zoai:estudogeral.uc.pt:10316/108247Portal AgregadorONGhttps://www.rcaap.pt/oai/openaireopendoar:71602024-03-19T21:24:33.402039Repositório Científico de Acesso Aberto de Portugal (Repositórios Cientìficos) - Agência para a Sociedade do Conhecimento (UMIC) - FCT - Sociedade da Informaçãofalse
dc.title.none.fl_str_mv Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
title Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
spellingShingle Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
Santos, S. P. Amor dos
Hadron-Hadron scattering (experiments)
title_short Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
title_full Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
title_fullStr Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
title_full_unstemmed Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
title_sort Measurements of top-quark pair to Z-boson cross-section ratios at √s=13 , 8, 7 TeV with the ATLAS detector
author Santos, S. P. Amor dos
author_facet Santos, S. P. Amor dos
Carvalho, J.
Fiolhais, M. C. N.
Galhardo, B.
Veloso, F.
Wolters, H.
ATLAS Collaboration
author_role author
author2 Carvalho, J.
Fiolhais, M. C. N.
Galhardo, B.
Veloso, F.
Wolters, H.
ATLAS Collaboration
author2_role author
author
author
author
author
author
dc.contributor.author.fl_str_mv Santos, S. P. Amor dos
Carvalho, J.
Fiolhais, M. C. N.
Galhardo, B.
Veloso, F.
Wolters, H.
ATLAS Collaboration
dc.subject.por.fl_str_mv Hadron-Hadron scattering (experiments)
topic Hadron-Hadron scattering (experiments)
description 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.
publishDate 2017
dc.date.none.fl_str_mv 2017
dc.type.status.fl_str_mv info:eu-repo/semantics/publishedVersion
dc.type.driver.fl_str_mv info:eu-repo/semantics/article
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status_str publishedVersion
dc.identifier.uri.fl_str_mv http://hdl.handle.net/10316/108247
http://hdl.handle.net/10316/108247
https://doi.org/10.1007/JHEP02(2017)117
url http://hdl.handle.net/10316/108247
https://doi.org/10.1007/JHEP02(2017)117
dc.language.iso.fl_str_mv eng
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dc.publisher.none.fl_str_mv Springer Nature
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