Measurement of W-+/- boson production in Pb plus Pb collisions at root s(NN)=5.02 TeV with the ATLAS detector

Abstract

WOS: 000505550100001 ; A measurement of W-+/- boson production in Pb+Pb collisions at root s(NN) = 5.02 TeV is reported using data recorded by the ATLAS experiment at the LHC in 2015, corresponding to a total integrated luminosity of 0.49 nb(-1). The W-+/- bosons are reconstructed in the electron or muon leptonic decay channels. Production yields of leptonically decaying W-+/- bosons, normalised by the total number of minimum-bias events and the nuclear thickness function, are measured within a fiducial region defined by the detector acceptance and the main kinematic requirements. These normalised yields are measured separately for W+ and W- bosons, and are presented as a function of the absolute value of pseudorapidity of the charged lepton and of the collision centrality. The lepton charge asymmetry is also measured as a function of the absolute value of lepton pseudorapidity. In addition, nuclear modification factors are calculated using the W-+/- boson production cross-sections measured in pp collisions. The results are compared with predictions based on next-to-leading-order calculations with CT14 parton distribution functions as well as with predictions obtained with the EPPS16 and nCTEQ15 nuclear parton distribution functions. No dependence of normalised production yields on centrality and a good agreement with predictions are observed for mid-central and central collisions. For peripheral collisions, the data agree with predictions within 1.7 (0.9) standard deviations for W- (W+) bosons. ; CERN; ANPCyT, ArgentinaANPCyT; YerPhI, Armenia; ARC, AustraliaAustralian Research Council; BMWFW; FWF, AustriaAustrian Science Fund (FWF); ANASAzerbaijan National Academy of Sciences (ANAS); SSTC, Belarus; CNPqNational Council for Scientific and Technological Development (CNPq); FAPESP, BrazilFundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP); NSERCNatural Sciences and Engineering Research Council of Canada; CFI, CanadaCanada Foundation for Innovation; CONICYTComision Nacional de Investigacion Cientifica y Tecnologica (CONICYT); NSFC, ChinaNational Natural Science Foundation of China; COLCIENCIAS, ColombiaDepartamento Administrativo de Ciencia, Tecnologia e Innovacion Colciencias; MSMT CRMinistry of Education, Youth & Sports - Czech Republic; MPO CR; VSC CR, Czech RepublicCzech Republic Government; DNRF; DNSRC, DenmarkDanish Natural Science Research Council; IN2P3-CNRS, CEA-DRF/IRFU, France; BMBFFederal Ministry of Education & Research (BMBF); MPG, GermanyMax Planck Society; GSRT, GreeceGreek Ministry of Development-GSRT; RGC, Hong Kong SAR, ChinaHong Kong Research Grants Council; ISFIsrael Science Foundation; Benoziyo Center, Israel; INFN, ItalyIstituto Nazionale di Fisica Nucleare; MEXTMinistry 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; NWO, Netherlands; RCN, Norway; MNiSWMinistry 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; ARRSSlovenian Research Agency - Slovenia; MIZS, Slovenia; MINECO, Spain; Wallenberg Foundation, Sweden; SNSFSwiss National Science Foundation (SNSF); MOST, TaiwanMinistry of Science and Technology, Taiwan; TAEK, TurkeyMinistry of Energy & Natural Resources - Turkey; STFC, United KingdomScience & Technology Facilities Council (STFC); DOEUnited States Department of Energy (DOE); NSFNational Science Foundation (NSF); BCKDF; CANARIE; COST, ERC; ERDFEuropean Union (EU); Marie Sklodowska-Curie Actions, European UnionEuropean Union (EU); Investissements d' Avenir LabexFrench National Research Agency (ANR); ANR, FranceFrench National Research Agency (ANR); DFGGerman Research Foundation (DFG); AvH Foundation, Germany - EUESFAlexander von Humboldt Foundation; Greek NSRF, Greece; BSF-NSF; GIF, IsraelGerman-Israeli Foundation for Scientific Research and Development; CERCA Programme Generalitat de Catalunya, Spain; Royal SocietyRoyal Society of London; Leverhulme Trust, United KingdomLeverhulme Trust; NDGF(Denmark, Norway, Sweden); KIT/GridKA (Germany); INFN-CNAF (Italy); NL-T1 (Netherlands), PIC (Spain); ASGC (Taiwan); BNL (USA) ; 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; COLCIENCIAS, 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, United Kingdom; DOE and NSF, United States of America. 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 EUESF and the Greek NSRF, Greece; BSF-NSF and GIF, Israel; CERCA Programme Generalitat de Catalunya, Spain; The Royal Society and Leverhulme Trust, United Kingdom. The crucial computing support from all WLCG partners is acknowledged gratefully, in particular from CERN, theATLAS 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. [78].