Pion, Kaon, and Proton Production in Central Pb-Pb Collisions at root s(NN)=2.76 TeV
ALICE Collaboration (ukupan broj autora: 991)
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In this Letter we report the first results on pi(+/-), K-+/-, p, and (p) over bar production at midrapidity (vertical bar y vertical bar LT 0.5) in central Pb-Pb collisions at root s(NN) = 2.76 TeV, measured by the ALICE experiment at the LHC. The p(T) distributions and yields are compared to previous results at root s(NN) = 200 GeV and expectations from hydrodynamic and thermal models. The spectral shapes indicate a strong increase of the radial flow velocity with root s(NN), which in hydrodynamic models is expected as a consequence of the increasing particle density. While the K/pi ratio is in line with predictions from the thermal model, the p/pi ratio is found to be lower by a factor of about 1.5. This deviation from thermal model expectations is still to be understood.
Source:Physical Review Letters, 2012, 109, 25
- Calouste Gulbenkian Foundation from Lisbon and Swiss Fonds Kidagan, Armenia, Conselho Nacional de Desenvolvimento Cientifico e Tecnologico (CNPq), Financiadora de Estudos e Projetos (FINEP), Fundacao de Amparo a Pesquisa do Estado de Sao Paulo (FAPESP), National Natural Science Foundation of China (NSFC), Chinese Ministry of Education (CMOE), Ministry of Science and Technology of China (MSTC), Ministry of Education and Youth of the Czech Republic, Danish Natural Science Research Council, Carlsberg Foundation, Danish National Research Foundation, European Research Council under the European Community, Helsinki Institute of Physics, Academy of Finland, French CNRS-IN2P3, Region Pays de Loire, Region Alsace, Region Auvergne, CEA, France, German BMBF, Helmholtz Association, General Secretariat for Research and Technology, Ministry of Development, Greece, Hungarian OTKA, National Office for Research and Technology (NKTH), Department of Atomic Energy, Department of Science and Technology of the Government of India, Istituto Nazionale di Fisica Nucleare (INFN) of Italy, MEXT Grant-in-Aid for Specially Promoted Research, Japan, Joint Institute for Nuclear Research, Dubna, National Research Foundation of Korea (NRF), CONACYT, DGAPA, Mexico, ALFA-EC, HELEN Program (High-Energy physics Latin-American-European Network), Stichting voor Fundamenteel Onderzoek der Materie (FOM), Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands, Research Council of Norway (NFR), Polish Ministry of Science and Higher Education, 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, International Science and Technology Center, Russian Academy of Sciences, Russian Federal Agency of Atomic Energy, Russian Federal Agency for Science and Innovations, CERN-INTAS, Ministry of Education of Slovakia, CIEMAT, EELA, Ministerio de Educacion y Ciencia of Spain, Xunta de Galicia (Conselleria de Educacion), CEADEN, Cubaenergia, Cuba, IAEA (International Atomic Energy Agency), Ministry of Science and Technology and the National Research Foundation (NRF), South Africa, Swedish Reseach Council (VR), Knut and Alice Wallenberg Foundation (KAW), Ukraine Ministry of Education and Science, United Kingdom Science and Technology Facilities Council (STFC), United States Department of Energy, United States National Science Foundation, State of Texas, State of Ohio