

Measurements of joint-polarisation states of W and Z gauge bosons in W±Z production are presented. The data set used corresponds to an integrated luminosity of 139 fb−1 of proton–proton collisions at a centre-of-mass energy of 13 TeV recorded by the ATLAS detector at the CERN Large Hadron Collider. The W±Z candidate events are reconstructed using leptonic decay modes of the gauge bosons into electrons and muons. The simultaneous pair-production of longitudinally polarised vector bosons is measured for the first time with a significance of 7.1 standard deviations. The measured joint helicity fractions integrated over the fiducial region are f00=0.067±0.010, f0T=0.110±0.029, fT0=0.179±0.023 and fTT=0.644±0.032, in agreement with the next-to-leading-order Standard Model predictions. Individual helicity fractions of the W and Z bosons are also measured and found to be consistent with joint helicity fractions within the expected amounts of correlation. Both the joint and individual helicity fractions are also measured separately in W+Z and W−Z events. Inclusive and differential cross sections for several kinematic observables sensitive to polarisation are presented. © 2023
| Funding sponsor | Funding number | Acronym |
|---|---|---|
| IN2P3-CNRS | ||
| CC-IN2P3 | ||
| 2014-2021 | ||
| National Science Foundation See opportunities by NSF | NSF | |
| U.S. Department of Energy See opportunities by USDOE | USDOE | |
| Alexander von Humboldt-Stiftung See opportunities by AvH | AvH | |
| Alabama Space Grant Consortium See opportunities by ASGC | ASGC | |
| Brookhaven National Laboratory See opportunities by BNL | BNL | |
| Karlsruhe Institute of Technology | KIT | |
| H2020 Marie Skłodowska-Curie Actions See opportunities by MSCA | MSCA | |
| Multiple Sclerosis Scientific Research Foundation | MSSRF | |
| CERN | ||
| Göran Gustafssons Stiftelser | ||
| Azərbaycan Milli Elmlər Akademiyası | AMEA | |
| Natural Sciences and Engineering Research Council of Canada See opportunities by NSERC | NSERC | |
| National Research Council Canada See opportunities by NRC | NRC | |
| Canada Foundation for Innovation | CFI | |
| Science and Technology Facilities Council See opportunities by STFC | STFC | |
| Leverhulme Trust See opportunities | ||
| European Research Council | ERC | |
| European Cooperation in Science and Technology | COST | |
| Australian Research Council See opportunities by ARC | ARC | |
| National Stroke Foundation | NSF | |
| Neurosurgical Research Foundation | NRF | |
| Helmholtz-Gemeinschaft See opportunities by HGF | HGF | |
| Deutsche Forschungsgemeinschaft See opportunities by DFG | DFG | |
| Agence Nationale de la Recherche See opportunities by ANR | ANR | |
| Japan Society for the Promotion of Science See opportunities by KAKEN | KAKEN | |
| Ministry of Education, Culture, Sports, Science and Technology | MEXT | |
| Schweizerischer Nationalfonds zur Förderung der Wissenschaftlichen Forschung See opportunities by SNF | SNF | |
| Danmarks Grundforskningsfond | DNRF | |
| Fundação de Amparo à Pesquisa do Estado de São Paulo See opportunities by FAPESP | FAPESP | |
| National Natural Science Foundation of China | NSFC | |
| Ministerstvo Školství, Mládeže a Tělovýchovy | MŠMT | |
| Fundação para a Ciência e a Tecnologia See opportunities by FCT | FCT | |
| Bundesministerium für Bildung und Forschung | BMBF | |
| Chinese Academy of Sciences | CAS | |
| Austrian Science Fund | FWF | |
| Generalitat de Catalunya | ||
| Ministry of Science and Technology of the People's Republic of China | MOST | |
| Agencia Nacional de Promoción Científica y Tecnológica | ANPCyT | |
| Nederlandse Organisatie voor Wetenschappelijk Onderzoek | NWO | |
| Bundesministerium für Wissenschaft, Forschung und Wirtschaft | BMWFW | |
| Conselho Nacional de Desenvolvimento Científico e Tecnológico | CNPq | |
| Joint Institute for Nuclear Research | JINR | |
| Nella and Leon Benoziyo Center for Neurological Diseases, Weizmann Institute of Science | ||
| Israel Science Foundation | ISF | |
| Instituto Nazionale di Fisica Nucleare | INFN | |
| Narodowe Centrum Nauki | NCN | |
| Javna Agencija za Raziskovalno Dejavnost RS | ARRS | |
| Ministarstvo Prosvete, Nauke i Tehnološkog Razvoja | MPNTR | |
| Ministerio de Ciencia e Innovación | MICINN | |
| Centre National pour la Recherche Scientifique et Technique | CNRST | |
| Staatssekretariat für Bildung, Forschung und Innovation | SBFI | |
| Horizon 2020 | ||
| British Columbia Knowledge Development Fund | BCKDF | |
| European Regional Development Fund | ERDF | |
| Defence Science Institute | DSI | |
| Council on grants of the President of the Russian Federation | ||
| National Research Center "Kurchatov Institute" | NRC KI | |
| Narodowa Agencja Wymiany Akademickiej | NAWA | |
| Agencia Nacional de Investigación y Desarrollo | ANID | |
| Royal Society of South Australia | RSSA | |
| Irish Rugby Football Union | IRFU |
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; ANID, Chile; CAS, MOST and NSFC, China; Minciencias, Colombia; MEYS CR, Czech Republic; DNRF and DNSRC, Denmark; IN2P3-CNRS and CEA-DRF/IRFU, France; SRNSFG, Georgia; BMBF, HGF and MPG, Germany; GSRI, Greece; RGC and Hong Kong SAR, China; ISF and Benoziyo Center, Israel; INFN, Italy; MEXT and JSPS, Japan; CNRST, Morocco; NWO, Netherlands; RCN, Norway; MEiN, Poland; FCT, Portugal; MNE/IFA, Romania; JINR; MES of Russia and NRC KI, Russian Federation; MESTD, Serbia; MSSR, Slovakia; ARRS and MIZŠ, Slovenia; DSI/NRF, South Africa; MICINN, Spain; SRC and Wallenberg Foundation, Sweden; SERI, SNSF and Cantons of Bern and Geneva, Switzerland; MOST, Taiwan; TENMAK, Türkiye; STFC, United Kingdom; DOE and NSF, United States of America. In addition, individual groups and members have received support from BCKDF, Canarie, Compute Canada and CRC, Canada; COST, ERC, ERDF, Horizon 2020 and Marie Skłodowska-Curie Actions, European Union; Investissements d'Avenir Labex, Investissements d'Avenir Idex and ANR, France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF, Greece; BSF-NSF and GIF, Israel; Norwegian Financial Mechanism 2014-2021, Norway; NCN and NAWA, Poland; La Caixa Banking Foundation, CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana, Spain; Göran Gustafssons Stiftelser, Sweden; 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 (UK) and BNL (USA), the Tier-2 facilities worldwide and large non-WLCG resource providers. Major contributors of computing resources are listed in Ref. [99].
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 ; ANID , Chile; CAS , MOST and NSFC , China; Minciencias , Colombia; MEYS CR, Czech Republic; DNRF and DNSRC , Denmark; IN2P3-CNRS and CEA-DRF/IRFU , France; SRNSFG , Georgia; BMBF , HGF and MPG , Germany; GSRI , Greece; RGC and Hong Kong SAR , China; ISF and Benoziyo Center , Israel; INFN , Italy; MEXT and JSPS , Japan; CNRST , Morocco; NWO , Netherlands; RCN , Norway; MEiN , Poland; FCT , Portugal; MNE/IFA , Romania; JINR ; MES of Russia and NRC KI , Russian Federation; MESTD , Serbia; MSSR , Slovakia; ARRS and MIZŠ , Slovenia; DSI/NRF , South Africa; MICINN , Spain; SRC and Wallenberg Foundation , Sweden; SERI , SNSF and Cantons of Bern and Geneva , Switzerland; MOST , Taiwan; TENMAK , Türkiye; STFC , United Kingdom; DOE and NSF , United States of America. In addition, individual groups and members have received support from BCKDF , Canarie , Compute Canada and CRC , Canada; COST , ERC , ERDF , Horizon 2020 and Marie Skłodowska-Curie Actions , European Union; Investissements d'Avenir Labex , Investissements d'Avenir Idex and ANR , France; DFG and AvH Foundation, Germany; Herakleitos, Thales and Aristeia programmes co-financed by EU-ESF and the Greek NSRF , Greece; BSF-NSF and GIF , Israel; Norwegian Financial Mechanism 2014-2021 , Norway; NCN and NAWA , Poland; La Caixa Banking Foundation , CERCA Programme Generalitat de Catalunya and PROMETEO and GenT Programmes Generalitat Valenciana , Spain; Göran Gustafssons Stiftelser , Sweden; The Royal Society and Leverhulme Trust , United Kingdom.
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