Measurement of charm and beauty production at central rapidity versus charged-particle multiplicity in proton-proton collisions at root s=7 TeV
ALICE Collaboration (ukupan broj autora: 974)
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Prompt D meson and non-prompt J/psi yields are studied as a function of the multiplicity of charged particles produced in inelastic proton-proton collisions at a centre-of-mass energy of root s = 7 TeV. The results are reported as a ratio between yields in a given multiplicity interval normalised to the multiplicity-integrated ones (relative yields). They are shown as a function of the multiplicity of charged particles normalised to the average value for inelastic collisions (relative charged-particle multiplicity). D-0, D+ and D*+ mesons are measured in five p(T) intervals from 1 GeV/c to 20 GeV/c and for |y| LT 0.5 via their hadronic decays. The D-meson relative yield is found to increase with increasing charged-particle multiplicity. For events with multiplicity six times higher than the average multiplicity of inelastic collisions, a yield enhancement of a factor about 15 relative to the multiplicity-integrated yield in inelastic collisions is observed. The yield enhancement is ind...ependent of transverse momentum within the uncertainties of the measurement. The D-0-meson relative yield is also measured as a function of the relative multiplicity at forward pseudo-rapidity. The non-prompt J/psi, i.e. the B hadron, contribution to the inclusive J/psi production is measured in the di-electron decay channel at central rapidity. It is evaluated for p(T) GT 1.3 GeV/c and |y| LT 0.9, and extrapolated to p(T) GT 0. The fraction of non-prompt J/psi the inclusive J/psi yields shows no dependence on the charged-particle multiplicity at central rapidity. Charm and beauty hadron relative yields exhibit a similar increase with increasing charged-particle multiplicity. The measurements are compared to PYTHIA 8, EPOS 3 and percolation calculations.
Source:Journal of High Energy Physics, 2015, 9
- State Committee of Science, World Federation of Scientists (WFS), 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 Communitys Seventh Framework Programme, Helsinki Institute of Physics, Academy of Finland, French CNRS-IN2P3, France, Region Pays de Loire, France, Region Alsace, France, Region Auvergne, France, CEA, France, German Bundesministerium fur Bildung, Wissenschaft, Forschung und Technologie (BMBF), Helmholtz Association, General Secretariat for Research and Technology, Ministry of Development, Greece, Hungarian Orszagos Tudomanyos Kutatasi Alappgrammok (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), Italy, Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche Enrico Fermi, Italy, MEXT, 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), Mexico, Amerique Latine Formation academique - European Commission (ALFA-EC), EPLANET Program (European Particle Physics Latin American Network), Stichting voor Fundamenteel Onderzoek der Materie (FOM), Netherlands, Nederlandse Organisatie voor Wetenschappelijk Onderzoek (NWO), Netherlands, Research Council of Norway (NFR), National Science Centre, Poland, Ministry of National Education/Institute for Atomic Physics, Romania, National Council of Scientific Research in Higher Education (CNCSI-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, Russian Foundation for Basic Research, Ministry of Education of Slovakia, Department of Science and Technology, South Africa, Centro de Investigaciones Energeticas, Medioambientales y Tecnologicas (CIEMAT), E-Infrastructure shared between Europe and Latin America (EELA), Ministerio de Economia y Competitividad (MINECO) of Spain, Xunta de Galicia (Conselleria de Educacion), IAEA (International Atomic Energy Agency), Swedish Research 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, Ministry of Science, Education and Sports of Croatia, Unity through Knowledge Fund, Croatia, Grid centres, Worldwide LHC Computing Grid (WLCG) collaboration, Centro de Aplicaciones Tecnologicas y Desarrollo Nuclear (CEADEN), Cubaenergia, Cuba