Two-particle azimuthal correlations in photonuclear ultraperipheral Pb+Pb collisions at 5.02 TeV with ATLAS
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American Physical Society
G. Aad et al. (ATLAS Collaboration) (2021). Two-particle azimuthal correlations in photonuclear ultraperipheral Pb+Pb collisions at 5.02 TeV with ATLAS. Phys. Rev. C 104, 014903. DOI: [10.1103/PhysRevC.104.014903]
SponsorshipANPCyT; Australian Research Council; Austrian Science Fund (FWF); SSTC, Belarus; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); Natural Sciences and Engineering Research Council of Canada (NSERC) Canada Foundation for Innovation; National Natural Science Foundation of China (NSFC); Departamento Administrativo de Ciencia, Tecnologia e Innovacion Colciencias; Ministry of Education, Youth & Sports - Czech Republic Czech Republic Government Czech Republic Government; Danish Natural Science Research Council; CEA-DRF/IRFU, France; Max Planck Society; RGC and Hong Kong SAR, China; Israel Science Foundation Benoziyo Center, Israel; Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Ministry of Education, Culture, Sports, Science and Technology, Japan (MEXT) Japan Society for the Promotion of Science; CNRST, Morocco; Ministry of Science and Higher Education, Poland NCN, Poland; Portuguese Foundation for Science and Technology European Commission; Ministry of Education, Science & Technological Development, Serbia; Slovenian Research Agency - Slovenia MIZS, Slovenia; Spanish Government; Wallenberg Foundation, Sweden; SNSF Geneva, Switzerland; National Science Foundation (NSF); BCKDF, Canada CANARIE, Canada; Beijing Municipal Science & Technology Commission; ERC, France ERDF, France Marie Sklodowska-Curie Actions, France French National Research Agency (ANR); Alexander von Humboldt Foundation; EU-ESF, Greece Greek NSRF, Greece; BSF-NSF, Israel German-Israeli Foundation for Scientific Research and Development; CERCA Programme Generalitat de Catalunya, Spain PROMETEO, Spain GenT Programmes Generalitat Valenciana, Spain; Goran Gustafssons Stiftelse, Sweden; Royal Society of London Leverhulme Trust; YerPhI, Australia Armenia, Australia; BMWFW, Austria; ANAS, Belarus Azerbaijan, Belarus; Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPQ); NRC, Canada; CERN, Chile ANID, Chile; Chinese Academy of Sciences Ministry of Science and Technology, China; DNRF, Denmark; Centre National de la Recherche Scientifique (CNRS); SRNSFG, Germany Georgia, Germany; Federal Ministry of Education & Research (BMBF); HGF, Germany; Greek Ministry of Development-GSRT; Istituto Nazionale di Fisica Nucleare (INFN); Netherlands Organization for Scientific Research (NWO) Netherlands Government; RCN, Norway; MNE/IFA, Romania; JINR, Russia MES of Russia; NRC KI, Serbia Russian Federation, Serbia; MSSR, Slovakia; DST/NRF, South Africa; SRC, Sweden; SERI, Geneva, Switzerland Cantons of Bern Geneva, Switzerland; Ministry of Science and Technology, Taiwan; Ministry of Energy & Natural Resources - Turkey; UK Research & Innovation (UKRI); Science & Technology Facilities Council (STFC); United States Department of Energy (DOE); Compute Canada, Canada CRC, Canada IVADO, Canada; COST, France Horizon 2020, France European Union, France; French National Research Agency (ANR); German Research Foundation (DFG); La Caixa Banking Foundation, Spain
Two-particle long-range azimuthal correlations are measured in photonuclear collisions using 1.7 nb−1 of 5.02 TeV Pb+Pb collision data collected by the ATLAS experiment at the CERN Large Hadron Collider. Candidate events are selected using a dedicated high-multiplicity photonuclear event trigger, a combination of information from the zero-degree calorimeters and forward calorimeters, and from pseudorapidity gaps constructed using calorimeter energy clusters and charged-particle tracks. Distributions of event properties are compared between data and Monte Carlo simulations of photonuclear processes. Two-particle correlation functions are formed using charged-particle tracks in the selected events, and a template-fitting method is employed to subtract the nonflow contribution to the correlation. Significant nonzero values of the secondand third-order flow coefficients are observed and presented as a function of charged-particle multiplicity and transverse momentum. The results are compared with flow coefficients obtained in proton-proton and proton-lead collisions in similar multiplicity ranges, and with theoretical expectations. The unique initial conditions present in this measurement provide a new way to probe the origin of the collective signatures previously observed only in hadronic collisions.