Medium-Induced Modification of Z-Tagged Charged Particle Yields in Pb + Pb Collisions at 5.02 TeV with the ATLAS Detector

Abstract

The yield of charged particles opposite to a Z boson with large transverse momentum (p(T)) is measured in 260 pb(-1) of pp and 1.7 nb(-1) of Pb + Pb collision data at 5.02 TeV per nucleon pair recorded with the ATLAS detector at the Large Hadron Collider. The Z boson tag is used to select hard-scattered partons with specific kinematics, and to observe how their showers are modified as they propagate through the quarkgluon plasma created in Pb + Pb collisions. Compared with pp collisions, charged-particle yields in Pb + Pb collisions show significant modifications as a function of charged-particle p(T) in a way that depends on event centrality and Z boson p(T). The data are compared with a variety of theoretical calculations and provide new information about the medium-induced energy loss of partons in a p(T) regime difficult to measure through other channels. ; ANPCyT ; YerPhI, Armenia ; Australian Research Council ; BMWFW, Austria ; Austrian Science Fund (FWF) ; Azerbaijan National Academy of Sciences (ANAS) ; SSTC, Belarus ; National Council for Scientific and Technological Development (CNPq) ; Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) ; Natural Sciences and Engineering Research Council of Canada (NSERC) ; NRC, Canada ; Canada Foundation for Innovation ; CERN ; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT) ; Chinese Academy of Sciences ; Ministry of Science and Technology, China ; National Natural Science Foundation of China (NSFC) ; Departamento Administrativo de Ciencia, Tecnología e Innovación Colciencias ; Ministry of Education, Youth & Sports - Czech Republic Czech Republic Government ; Czech Republic Government ; DNRF, Denmark ; Danish Natural Science Research Council ; Centre National de la Recherche Scientifique (CNRS) ; CEA-DRF/IRFU, France ; SRNSFG, Georgia ; Federal Ministry of Education & Research (BMBF) ; HGF, Germany ; Max Planck Society ; Greek Ministry of Development-GSRT ; RGC, China ; Hong Kong SAR, China ; Israel Science Foundation ; Benoziyo Center, Israel ; Istituto Nazionale di Fisica Nucleare (INFN) ; 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 ; Netherlands Organization for Scientific Research (NWO) Netherlands Government ; RCN, Norway ; Ministry of Science and Higher Education, Poland ; NCN, Poland ; Portuguese Foundation for Science and Technology European Commission ; MNE/IFA, Romania ; MES of Russia, Russia Federation ; NRC KI, Russia Federation ; JINR ; MESTD, Serbia ; MSSR, Slovakia ; Slovenian Research Agency - Slovenia ; MIZS, Slovenia ; DST/NRF, South Africa ; Spanish Government ; SRC, Sweden ; Wallenberg Foundation, Sweden ; SERI, Switzerland ; Swiss National Science Foundation (SNSF) ; Canton of Bern, Switzerland ; Canton of 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) ; National Science Foundation (NSF) ; BCKDF, Canada ; CANARIE, Canada ; Compute Canada, Canada ; CRC, Canada ; European Research Council (ERC) ; ERDF, European Union ; Horizon 2020, European Union ; Marie Sklodowska-Curie Actions, European Union ; COST, European Union ; French National Research Agency (ANR) ; German Research Foundation (DFG) ; Alexander von Humboldt Foundation ; Thales programme ; Aristeia programme ; EU-ESF, Greece ; Greek NSRF, Greece ; BSF-NSF, Israel ; German-Israeli Foundation for Scientific Research and Development ; La Caixa Banking Foundation, Spain ; CERCA Programme Generalitat de Catalunya, Spain ; PROMETEO Programme Generalitat Valenciana, Spain ; GenT Programme Generalitat Valenciana, Spain ; Goran Gustafssons Stiftelse, Sweden ; Royal Society of London ; Leverhulme Trust