Abstract
The transverse momentum (pT) spectrum and nuclear modification factor (RAA) of reconstructed jets in 0–10% and 10–30% central Pb–Pb collisions at sNN=2.76 TeV were measured. Jets were reconstructed using the anti-kT jet algorithm with a resolution parameter of R=0.2 from charged and neutral particles, utilizing the ALICE tracking detectors and Electromagnetic Calorimeter (EMCal). The jet pT spectra are reported in the pseudorapidity interval of |ηjet|<0.5 for 40<pT,jet<120 GeV/c in 0–10% and for 30<pT,jet<100 GeV/c in 10–30% collisions. Reconstructed jets were required to contain a leading charged particle with pT>5 GeV/c to suppress jets constructed from the combinatorial background in Pb–Pb collisions. The leading charged particle requirement applied to jet spectra both in pp and Pb–Pb collisions had a negligible effect on the RAA. The nuclear modification factor RAA was found to be 0.28±0.04 in 0–10% and 0.35±0.04 in 10–30% collisions, independent of pT,jet within the uncertainties of the measurement. The observed suppression is in fair agreement with expectations from two model calculations with different approaches to jet quenching.
Original language | English |
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Pages (from-to) | 1-14 |
Number of pages | 14 |
Journal | Physics Letters B |
Volume | 746 |
DOIs | |
State | Published - Jun 30 2015 |
Externally published | Yes |
Funding
The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centers and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: State Committee of Science, World Federation of Scientists (WFS) and Swiss Fonds Kidagan, Armenia; Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP); National Natural Science Foundation of China (NSFC), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC); Ministry of Education and Youth of the Czech Republic; Danish Natural Science Research Council, the Carlsberg Foundation and the Danish National Research Foundation; The European Research Council under the European Community's Seventh Framework Programme; Helsinki Institute of Physics and the Academy of Finland; French CNRS–IN2P3, the ‘Region Pays de Loire’ ‘Region Alsace’ ‘Region Auvergne’ and CEA, France; German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie (BMBF) and the Helmholtz Association; General Secretariat for Research and Technology, Ministry of Development, Greece; Hungarian Orszagos Tudomanyos Kutatasi Alappgrammok (OTKA) and National Office for Research and Technology (NKTH); Department of Atomic Energy and Department of Science and Technology of the Government of India; Istituto Nazionale di Fisica Nucleare (INFN) and Centro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi” Italy; MEXT Grant-in-Aid for Specially Promoted Research, Japan; Joint Institute for Nuclear Research, Dubna; National Research Foundation of Korea (NRF); Consejo Nacional de Cienca y Tecnologia (CONACYT), Direccion General de Asuntos del Personal Academico (DGAPA), México, Amerique Latine Formation academique–European Commission (ALFA–EC) and the EPLANET Program (European Particle Physics Latin American Network); Stichting voor Fundamenteel Onderzoek der Materie (FOM) and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; Research Council of Norway (NFR); National Science Centre of Poland; Ministry of National Education/Institute for Atomic Physics and Consiliul Naţional al Cercetării Ştiinţifice–Executive Agency for Higher Education Research Development and Innovation Funding (CNCS–UEFISCDI), Romania; Ministry of Education and Science of Russian Federation, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research; Ministry of Education of Slovakia; Department of Science and Technology, Republic of South Africa; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America (EELA), Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellería de Educación), Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Cubaenergía, Cuba, and IAEA (International Atomic Energy Agency); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science; United Kingdom Science and Technology Facilities Council (STFC); The United States Department of Energy, the United States National Science Foundation, the State of Texas, and the State of Ohio; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund, Croatia. Council of Scientific and Industrial Research (CSIR), New Delhi, India. The ALICE Collaboration would like to thank all its engineers and technicians for their invaluable contributions to the construction of the experiment and the CERN accelerator teams for the outstanding performance of the LHC complex. The ALICE Collaboration gratefully acknowledges the resources and support provided by all Grid centers and the Worldwide LHC Computing Grid (WLCG) collaboration. The ALICE Collaboration acknowledges the following funding agencies for their support in building and running the ALICE detector: State Committee of Science , World Federation of Scientists (WFS) and Swiss Fonds Kidagan , Armenia; Conselho Nacional de Desenvolvimento Científico e Tecnológico ( CNPq ), Financiadora de Estudos e Projetos ( FINEP ), Fundação de Amparo à Pesquisa do Estado de São Paulo ( FAPESP ); National Natural Science Foundation of China ( NSFC ), the Chinese Ministry of Education (CMOE) and the Ministry of Science and Technology of China (MSTC); Ministry of Education and Youth of the Czech Republic ; Danish Natural Science Research Council , the Carlsberg Foundation and the Danish National Research Foundation ; The European Research Council under the European Community's Seventh Framework Programme ; Helsinki Institute of Physics and the Academy of Finland ; French CNRS–IN2P3 , the ‘Region Pays de Loire’, ‘Region Alsace’, ‘Region Auvergne’ and CEA , France; German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie ( BMBF ) and the Helmholtz Association ; General Secretariat for Research and Technology , Ministry of Development , Greece; Hungarian Orszagos Tudomanyos Kutatasi Alappgrammok ( OTKA ) and National Office for Research and Technology ( NKTH ); Department of Atomic Energy and Department of Science and Technology of the Government of India ; Istituto Nazionale di Fisica Nucleare ( INFN ) and Centro Fermi – Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi” , Italy; MEXT Grant-in-Aid for Specially Promoted Research, Japan; Joint Institute for Nuclear Research , Dubna; National Research Foundation of Korea (NRF); Consejo Nacional de Cienca y Tecnologia ( CONACYT ), Direccion General de Asuntos del Personal Academico ( DGAPA ), México, Amerique Latine Formation academique–European Commission ( ALFA–EC ) and the EPLANET Program (European Particle Physics Latin American Network); Stichting voor Fundamenteel Onderzoek der Materie ( FOM ) and the Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands; Research Council of Norway (NFR); National Science Centre of Poland ; Ministry of National Education/Institute for Atomic Physics and Consiliul Naţional al Cercetării Ştiinţifice–Executive Agency for Higher Education Research Development and Innovation Funding ( CNCS–UEFISCDI ), Romania; Ministry of Education and Science of Russian Federation , Russian Academy of Sciences , Russian Federal Agency of Atomic Energy , Russian Federal Agency for Science and Innovations and The Russian Foundation for Basic Research ; Ministry of Education of Slovakia ; Department of Science and Technology, Republic of South Africa ; Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America ( EELA ), Ministerio de Economía y Competitividad (MINECO) of Spain, Xunta de Galicia (Consellería de Educación), Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear ( CEADEN ), Cubaenergía , Cuba, and IAEA ( International Atomic Energy Agency ); Swedish Research Council (VR) and Knut & Alice Wallenberg Foundation (KAW); Ukraine Ministry of Education and Science ; United Kingdom Science and Technology Facilities Council (STFC); The United States Department of Energy , the United States National Science Foundation , the State of Texas, and the State of Ohio; Ministry of Science, Education and Sports of Croatia and Unity through Knowledge Fund , Croatia. Council of Scientific and Industrial Research (CSIR), New Delhi, India.
Funders | Funder number |
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Danish Natural Science Research Council | |
Department of Atomic Energy and Department of Science and Technology of the Government of India | |
Direccion General de Asuntos del Personal Academico ( DGAPA ), México, Amerique Latine Formation academique | |
General Secretariat for Research and Technology , Ministry of Development | |
Helsinki Institute of Physics | |
Hungarian Orszagos Tudomanyos Kutatasi Alappgrammok | |
Ministry of Education and Youth of the Czech Republic | |
Ministry of Education of Slovakia | |
Ministry of National Education/Institute for Atomic Physics and Consiliul Naţional al Cercetării Ştiinţifice–Executive Agency for Higher Education Research Development | |
Ministry of Science, Education and Sports of Croatia and Unity | |
NFR | |
Region Auvergne’ and CEA | |
Russian Federal Agency of Atomic Energy , Russian Federal Agency for Science and Innovations | |
State Committee of Science , World Federation | |
Swiss Fonds Kidagan | |
United Kingdom Science and Technology Facilities Council | |
Xunta de Galicia (Consellería de Educación | |
National Science Foundation | |
U.S. Department of Energy | |
Corporation for National and Community Service | |
Alabama Farmers Federation | |
Unity through Knowledge Fund | |
California Earthquake Authority | |
Science and Technology Facilities Council | 2014 STFC Nuclear Physics CG, ST/M001601/1, ST/L005689/1, ALICE, ST/L005751/1, GRIDPP, ST/J000094/1, ST/J000108/1, ST/L005670/1, ST/M00158X/1, ST/M001598/1 |
European Commission | |
European Research Council | |
Department of Science and Technology, Republic of South Africa | |
Department of Science and Technology, Ministry of Science and Technology, India | |
Council of Scientific and Industrial Research, India | |
Japan Society for the Promotion of Science | 15H03664, 25287048, 26610071, 26220707 |
Ministry of Education, Culture, Sports, Science and Technology | |
Stichting voor Fundamenteel Onderzoek der Materie | |
Danmarks Grundforskningsfond | |
Fundação de Amparo à Pesquisa do Estado de São Paulo | |
National Natural Science Foundation of China | |
Russian Foundation for Basic Research | |
Ministry of Education of the People's Republic of China | |
Academy of Finland | |
Bundesministerium für Bildung und Forschung | |
Russian Academy of Sciences | |
Ministry of Education | |
Carlsbergfondet | |
Ministry of Science and Technology of the People's Republic of China | |
Consejo Nacional de Ciencia y Tecnología | |
Nederlandse Organisatie voor Wetenschappelijk Onderzoek | |
Ministerio de Economía y Competitividad | |
Foundation for Fundamental Research on Matter | |
Ministry of Education and Science of the Russian Federation | |
General Secretariat for Research and Technology | |
Hungarian Scientific Research Fund | |
Conselho Nacional de Desenvolvimento Científico e Tecnológico | |
National Research Foundation of Korea | |
Joint Institute for Nuclear Research | |
Nemzeti Kutatási és Technológiai Hivatal | |
Instituto Nazionale di Fisica Nucleare | |
Knut och Alice Wallenbergs Stiftelse | |
Narodowe Centrum Nauki | |
Vetenskapsrådet | |
International Atomic Energy Agency | |
Centre National de la Recherche Scientifique | |
Financiadora de Estudos e Projetos | |
Seventh Framework Programme | |
Norges Forskningsråd | |
Unitatea Executiva pentru Finantarea Invatamantului Superior, a Cercetarii, Dezvoltarii si Inovarii | |
Bundesministerium für Bildung und Frauen | |
State Committee of Science | |
Ministry of Education and Science of Ukraine | |
Helmholtz Association | |
Centro de Investigaciones Energéticas, Medioambientales y Tecnológicas | |
Bundesministerium für Bildung, Wissenschaft, Forschung und Technologie | |
Institut National de Physique Nucléaire et de Physique des Particules | |
Conseil Régional des Pays de la Loire | |
Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi | |
Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear |