Transverse sphericity of primary charged particles in minimum bias proton-proton collisions at root s=0.9, 2.76 and 7 TeV
Contribuinte(s) |
UNIVERSIDADE DE SÃO PAULO |
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Data(s) |
06/11/2013
06/11/2013
2012
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Resumo |
Measurements of the sphericity of primary charged particles in minimum bias proton-proton collisions at root s = 0.9, 2.76 and 7 TeV with the ALICE detector at the LHC are presented. The observable is measured in the plane perpendicular to the beam direction using primary charged tracks with p(T) > 0.5 GeV/c in vertical bar eta vertical bar < 0.8. The mean sphericity as a function of the charged particle multiplicity at mid-rapidity (N-ch) is reported for events with different p(T) scales ("soft" and "hard") defined by the transverse momentum of the leading particle. In addition, the mean charged particle transverse momentum versus multiplicity is presented for the different event classes, and the sphericity distributions in bins of multiplicity are presented. The data are compared with calculations of standard Monte Carlo event generators. The transverse sphericity is found to grow with multiplicity at all collision energies, with a steeper rise at low N-ch, whereas the event generators show an opposite tendency. The combined study of the sphericity and the mean p(T) with multiplicity indicates that most of the tested event generators produce events with higher multiplicity by generating more back-to-back jets resulting in decreased sphericity (and isotropy). The PYTHIA6 generator with tune PERUGIA-2011 exhibits a noticeable improvement in describing the data, compared to the other tested generators. Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq) Financiadora de Estudos e Projetos (FINEP) Financiadora de Estudos e Projetos (FINEP) Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP) National Natural Science Foundation of China (NSFC) National Natural Science Foundation of China (NSFC) Chinese Ministry of Education (CMOE) Chinese Ministry of Education (CMOE) Ministry of Science and Technology of China (MSTC) Ministry of Science and Technology of China (MSTC) Ministry of Education and Youth of the Czech Republic Ministry of Education and Youth of the Czech Republic Danish Natural Science Research Council Danish Natural Science Research Council Carlsberg Foundation Carlsberg Foundation Danish National Research Foundation Danish National Research Foundation European Research Council under the European Communitys Seventh Framework Programme European Research Council under the European Community's Seventh Framework Programme Helsinki Institute of Physics Helsinki Institute of Physics Academy of Finland Academy of Finland French CNRS-IN2P3, France French CNRSIN2P3, France Region Pays de Loire, France Region Pays de Loire, France Region Alsace, France Region Alsace, France Region Auvergne, France Region Auvergne, France CEA, France CEA, France German BMBF German BMBF Helmholtz Association Helmholtz Association General Secretariat for Research and Technology, Ministry of Development, Greece General Secretariat for Research and Technology, Ministry of Development, Greece Hungarian OTKA Hungarian OTKA National Office for Research and Technology (NKTH) National Office for Research and Technology (NKTH) Department of Atomic Energy Department of Atomic Energy Department of Science and Technology of the Government of India Department of Science and Technology of the Government of India Istituto Nazionale di Fisica Nucleare (INFN) of Italy Istituto Nazionale di Fisica Nucleare (INFN) of Italy MEXT, Japan MEXT, Japan Institute for Nuclear Research, Dubna Institute for Nuclear Research, Dubna National Research Foundation of Korea (NRF) National Research Foundation of Korea (NRF) CONACYT CONACYT DGAPA, Mexico DGAPA, Mexico ALFAEC ALFA-EC HELEN Program (High-Energy physics Latin-American-European Network) HELEN Program (HighEnergy physics LatinAmericanEuropean Network) Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands Research Council of Norway (NFR) Research Council of Norway (NFR) Polish Ministry of Science and Higher Education Polish Ministry of Science and Higher Education National Authority for Scientific Research NASR (Autoritatea Nationala pentru Cercetare Stiintifica ANCS) National Authority for Scientific Research-NASR (Autoritatea Nationala pentru Cercetare, Stiintifica-ANCS) Federal Agency of Science of the Ministry of Education and Science of Russian Federation Federal Agency of Science of the Ministry of Education and Science of Russian Federation International Science and Technology Center International Science and Technology Center Russian Academy of Sciences Russian Academy of Sciences Russian Federal Agency of Atomic Energy Russian Federal Agency of Atomic Energy Russian Federal Agency for Science and Innovations Russian Federal Agency for Science and Innovations CERN-INTAS CERNINTAS Ministry of Education of Slovakia Ministry of Education of Slovakia Department of Science and Technology, South Africa Department of Science and Technology, South Africa CIEMAT CIEMAT EELA EELA Ministerio de Educacion y Ciencia of Spain Ministerio de Educacion y Ciencia of Spain Xunta de Galicia (Conselleria de Educacion) Xunta de Galicia (Conselleria de Educacion) CEADEN CEADEN Cubaenergia Cubaenergia Cuba Cuba IAEA (International Atomic Energy Agency) IAEA (International Atomic Energy Agency) Swedish Research Council (VR) Swedish Research Council (VR) Knut & Alice Wallenberg Foundation (KAW) Knut & Alice Wallenberg Foundation (KAW) Ukraine Ministry of Education and Science Ukraine Ministry of Education and Science United Kingdom Science and Technology Facilities Council (STFC) United Kingdom Science and Technology Facilities Council (STFC) United States Department of Energy United States Department of Energy United States National Science Foundation United States National Science Foundation State of Texas State of Texas State of Ohio State of Ohio |
Identificador |
EUROPEAN PHYSICAL JOURNAL C, NEW YORK, v. 72, n. 9, supl. 1, Part 3, pp. S145-S150, SEP, 2012 1434-6044 http://www.producao.usp.br/handle/BDPI/42573 10.1140/epjc/s10052-012-2124-9 |
Idioma(s) |
eng |
Publicador |
SPRINGER NEW YORK |
Relação |
EUROPEAN PHYSICAL JOURNAL C |
Direitos |
restrictedAccess Copyright SPRINGER |
Palavras-Chave | #3-JET EVENTS #ENERGIES #GLUON #LHC #PHYSICS, PARTICLES & FIELDS |
Tipo |
article original article publishedVersion |