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

Abstract

WOS: 000395022700001 ; 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, mu at 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 -> mu (+) mu (-) 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. ; ANPCyT, ArgentinaANPCyT; YerPHI, Armenia; ARC, AustraliaAustralian Research Council; BMWFW, Austria; FWF, AustriaAustrian Science Fund (FWF); ANAS, AzerbaijanAzerbaijan National Academy of Sciences (ANAS); SSTC, Belarus; CNPq, BrazilNational Council for Scientific and Technological Development (CNPq); FAPESP, BrazilFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); NSERC, CanadaNatural Sciences and Engineering Research Council of Canada; NRC, Canada; CFI, CanadaCanada Foundation for Innovation; CERN; CONICYT, ChileComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); CAS, ChinaChinese Academy of Sciences; MOST, ChinaMinistry of Science and Technology, China; NSFC, ChinaNational Natural Science Foundation of China; COLCIENCIAS, ColombiaDepartamento Administrativo de Ciencia, Tecnologia e Innovacion Colciencias; MSMT CR, Czech RepublicMinistry of Education, Youth & Sports - Czech RepublicCzech Republic Government; MPO CR, Czech RepublicCzech Republic Government; VSC CR, Czech RepublicCzech Republic Government; DNRF, Denmark; DNSRC, DenmarkDanish Natural Science Research Council; IN2P3-CNRS, FranceCentre National de la Recherche Scientifique (CNRS); CEA-DSM/IRFU, France; GNSF, Georgia; BMBF, GermanyFederal Ministry of Education & Research (BMBF); HGF, Germany; MPG, GermanyMax Planck Society; GSRT, GreeceGreek Ministry of Development-GSRT; RGC, China; Hong Kong SAR, China; ISF, IsraelIsrael Science Foundation; I-CORE, Israel; INFN, ItalyIstituto Nazionale di Fisica Nucleare; MEXT, JapanMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT); JSPS, JapanMinistry of Education, Culture, Sports, Science and Technology, Japan (MEXT)Japan Society for the Promotion of Science; CNRST, Morocco; FOM, NetherlandsFOM (The Netherlands)Netherlands Government; NWO, NetherlandsNetherlands Organization for Scientific Research (NWO)Netherlands Government; RCN, Norway; MNiSW, PolandMinistry of Science and Higher Education, Poland; NCN, Poland; FCT, PortugalPortuguese Foundation for Science and Technology; MNE/IFA, Romania; MES of Russia, Russian FederationRussian Federation; NRC KI, Russian Federation; JINR; MESTD, Serbia; MSSR, Slovakia; ARRS, SloveniaSlovenian Research Agency - Slovenia; DST/NRF, South Africa; MINECO, Spain; SRC, Sweden; Wallenberg Foundation, Sweden; SERI, Switzerland; SNSF, SwitzerlandSwiss National Science Foundation (SNSF); Cantons of Bern, Switzerland; Geneva, Switzerland; MOST, TaiwanMinistry of Science and Technology, Taiwan; TAEK, TurkeyMinistry of Energy & Natural Resources - Turkey; STFC, United KingdomScience & Technology Facilities Council (STFC); DOE, United States of AmericaUnited States Department of Energy (DOE); NSF, United States of AmericaNational Science Foundation (NSF); BCKDF, Canada; Canada Council, Canada; CANARIE, Canada; CRC, Canada; Compute Canada, Canada; FQRNT, CanadaFQRNT; Ontario Innovation Trust, Canada; ERC, European UnionEuropean Union (EU)European Research Council (ERC); Marie Sk lodowska-Curie Actions, European Union; EPLANET, European UnionEuropean Union (EU); Investissements d'Avenir Labex and Idex, FranceFrench National Research Agency (ANR); ANR, FranceFrench National Research Agency (ANR); Region Auvergne, FranceRegion Auvergne-Rhone-Alpes; Fondation Partager le Savoir, France; DFG, GermanyGerman Research Foundation (DFG); AvH Foundation, GermanyAlexander von Humboldt Foundation; Herakleitos programme - EU-ESF; Thales programme - EU-ESF; Greek NSRFGreek Ministry of Development-GSRT; BSF, IsraelUS-Israel Binational Science Foundation; GIF, IsraelGerman-Israeli Foundation for Scientific Research and Development; Minerva, Israel; BRF, Norway; Generalitat de Catalunya, SpainGeneralitat de Catalunya; Generalitat Valenciana, SpainGeneralitat Valenciana; Royal Society and Leverhulme Trust, United Kingdom; Benoziyo Center, Israel; MIZS, Slovenia; FP7, European UnionEuropean Union (EU); Horizon 2020, European Union; Aristeia programme - EU-ESF; Science and Technology Facilities CouncilScience & Technology Facilities Council (STFC) [1366825]; ICREAICREA ; 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 MIZS, 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, Region Auvergne and Fondation Partager le Savoir, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes cofinanced 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.