Measurement of W +/- Z production cross sections and gauge boson polarisation in pp collisions at root s=13 TeV with the ATLAS detector

Abstract

WOS: 000472517300002 ; This paper presents measurements of W +/- Z production cross sections in pp collisions at a centre-of-mass energy of 13TeV. The data were collected in 2015 and 2016 by the ATLAS experiment at the Large Hadron Collider, and correspond to an integrated luminosity of 36.1fb-1. The W +/- Z candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The measured inclusive cross section in the detector fiducial region for a single leptonic decay mode is sigma W +/- Zfid.=63.7fb, reproduced by the next-to-next-to-leading-order Standard Model prediction of 61.5-1.3+1.4fb. Cross sections for W+Z and W-Z production and their ratio are presented as well as differential cross sections for several kinematic observables. An analysis of angular distributions of leptons from decays of W and Z bosons is performed for the first time in pair-produced events in hadronic collisions, and integrated helicity fractions in the detector fiducial region are measured for the W and Z bosons separately. Of particular interest, the longitudinal helicity fraction of pair-produced vector bosons is also measured. ; 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; CFI, CanadaCanada Foundation for Innovation; CONICYT, ChileComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); NSFC, ChinaNational Natural Science Foundation of China; COLCIEN-CIAS, 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; CEA-DRF/IRFU, France; BMBF, GermanyFederal Ministry of Education & Research (BMBF); MPG, GermanyMax Planck Society; GSRT, GreeceGreek Ministry of Development-GSRT; RGC, Hong Kong SAR, ChinaHong Kong Research Grants Council; ISF, IsraelIsrael Science Foundation; Benoziyo Center, 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; RCN, Norway; MNiSW, PolandMinistry of Science and Higher Education, Poland; NCN, Poland; FCT, PortugalPortuguese Foundation for Science and Technology; MNE/IFA, Romania; NRC KI, Russian Federation; MESTD, Serbia; MSSR, Slovakia; ARRS, SloveniaSlovenian Research Agency - Slovenia; MIZS, Slovenia; MINECO, Spain; Wallenberg Foundation, Sweden; SNSF,Geneva, Switzerland; MOST, TaiwanMinistry of Science and Technology, Taiwan; TAEK, TurkeyMinistry of Energy & Natural Resources - Turkey; NSF, USANational Science Foundation (NSF); BCKDF, Canada; CANARIE, Canada; COSTEuropean Cooperation in Science and Technology (COST); ERDFEuropean Union (EU); Marie Sklodowska-Curie Actions, European UnionEuropean Union (EU); Investissements d' Avenir Labex, FranceFrench National Research Agency (ANR); ANR, FranceFrench National Research Agency (ANR); DFG, GermanyGerman Research Foundation (DFG); AvH Foundation, GermanyAlexander von Humboldt Foundation; Greek NSRF, Greece; GIF, IsraelGerman-Israeli Foundation for Scientific Research and Development; CERCA Programme Generalitat de Catalunya, Spain; Royal Society, UKRoyal Society of London; Leverhulme Trust, UKLeverhulme Trust; CERN; CAS, ChinaChinese Academy of Sciences; MOST, ChinaMinistry of Science and Technology, China; IN2P3-CNRS, FranceCentre National de la Recherche Scientifique (CNRS); SRNSFG,Georgia; HGF, Germany; NWO, NetherlandsNetherlands Organization for Scientific Research (NWO)Netherlands Government; MES of Russia; JINR; DST/NRF, South Africa; SRC, Sweden; SERI,Geneva, Switzerland; Cantons of Bern and Geneva, Switzerland; STFC, UKScience & Technology Facilities Council (STFC); DOE, USAUnited States Department of Energy (DOE); Compute Canada, Canada; ERCEuropean Research Council (ERC); Horizon 2020; Idex, France; EU-ESF, Greece; BSFNSF,Israel ; We thank CERN for the very successful operation of the LHC, as well as the support staff from our institutions without whom ATLAS could not be operated efficiently. 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; COLCIEN-CIAS, Colombia; MSMT CR, MPO CR and VSC CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS, CEA-DRF/IRFU, France; SRNSFG,Georgia; BMBF, HGF, and MPG, Germany; GSRT, Greece; RGC, Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; 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, UK; DOE and NSF, USA. In addition, individual groups and members have received support from BCKDF, CANARIE, CRC and Compute Canada, Canada; COST, ERC, ERDF, Horizon 2020, and Marie Sklodowska-Curie Actions, European Union; Investissements d' Avenir Labex and Idex, ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSFNSF and GIF, Israel; CERCA Programme Generalitat de Catalunya, Spain; The Royal Society and Leverhulme Trust, UK. 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 (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref. [106].