Published December 2010 | Version Published
Journal Article Open

First measurement of the underlying event activity at the LHC with √s = 0.9 TeV

Abstract

A measurement of the underlying activity in scattering processes with p_T scale in the GeV region is performed in proton–proton collisions at √s = 0.9 TeV, using data collected by the CMS experiment at the LHC. Charged particle production is studied with reference to the direction of a leading object, either a charged particle or a set of charged particles forming a jet. Predictions of several QCD inspired models as implemented in PYTHIA are compared, after full detector simulation, to the data. The models generally predict too little production of charged particles with pseudorapidity |η| < 2, p_T > 0.5 GeV/c, and azimuthal direction transverse to that of the leading object.

Additional Information

© 2010 CERN for benefit of the CMS collaboration. Open Access: This article is distributed under the terms of the Creative Commons Attribution Noncommercial License which permits any noncommercial use, distribution, and reproduction in any medium, provided the original author(s) and source are credited. Received: 10 June 2010; Revised: 3 September 2010; Published online: 6 November 2010. We wish to congratulate our colleagues in the CERN accelerator departments for the excellent performance of the LHC machine. We thank the technical and administrative staff at CERN and other CMS institutes for their devoted efforts during the design, construction and operation of CMS. The cost of the detectors, computing infrastructure, data acquisition and all other systems without which CMS would not be able to operate was supported by the financing agencies involved in the experiment. We are particularly indebted to: the Austrian Federal Ministry of Science and Research; the Belgium Fonds de la Recherche Scientifique, and Fonds voor Wetenschappelijk Onderzoek; the Brazilian Funding Agencies (CNPq, CAPES, FAPERJ, and FAPESP); the Bulgarian Ministry of Education and Science; CERN; the Chinese Academy of Sciences, Ministry of Science and Technology, and National Natural Science Foundation of China; the Colombian Funding Agency (COLCIENCIAS); the Croatian Ministry of Science, Education and Sport; the Research Promotion Foundation, Cyprus; the Estonian Academy of Sciences and NICPB; the Academy of Finland, Finnish Ministry of Education, and Helsinki Institute of Physics; the Institut National de Physique Nucléaire et de Physique des Particules/CNRS, and Commissariat à l'Énergie Atomique, France; the Bundesministerium für Bildung und Forschung, Deutsche Forschungsgemeinschaft, and Helmholtz- Gemeinschaft Deutscher For-schungszentren, Germany; the General Secretariat for Research and Technology, Greece; the National Scientific Research Foundation, and National Office for Research and Technology, Hungary; the Department of Atomic Energy, and Department of Science and Technology, India; the Institute for Studies in Theoretical Physics and Mathematics, Iran; the Science Foundation, Ireland; the Istituto Nazionale di Fisica Nucleare, Italy; the Korean Ministry of Education, Science and Technology and the World Class University program of NRF, Korea; the Lithuanian Academy of Sciences; the Mexican Funding Agencies (CINVESTAV, CONACYT, SEP, and UASLP-FAI); the Pakistan Atomic Energy Commission; the State Commission for Scientific Research, Poland; the Fundação para a Ciência e a Tecnologia, Portugal; JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan); the Ministry of Science and Technologies of the Russian Federation, and Russian Ministry of Atomic Energy; the Ministry of Science and Technological Development of Serbia; the Ministerio de Ciencia e Innovación, and Programa Consolider-Ingenio 2010, Spain; the Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH, Canton Zurich, and SER); the National Science Council, Taipei; the Scientific and Technical Research Council of Turkey, and Turkish Atomic Energy Authority; the Science and Technology Facilities Council, UK; the US Department of Energy, and the US National Science Foundation. Individuals have received support from the Marie-Curie IEF program (European Union); the Leventis Foundation; the A. P. Sloan Foundation; the Alexander von Humboldt Foundation; the Associazione per lo Sviluppo Scientifico e Tecnologico del Piemonte (Italy); the Belgian Federal Science Policy Office; the Fonds pour la Formation à la Recherche dans l'índustrie et dans l'Ágriculture (FRIA-Belgium); and the Agentschap voor Innovatie door Wetenschap en Technologie (IWT-Belgium).

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Additional details

Identifiers

Eprint ID
21971
Resolver ID
CaltechAUTHORS:20110202-122209591

Funding

Austrian Federal Ministry of Science and Research
Belgium Fonds de la Recherche Scientifique
Fonds voor Wetenschappelijk Onderzoek, Belgium
CNPq (Brazil)
CAPES (Brazil)
FAPERJ (Brazil)
FAPESP (Brazil)
Bulgarian Ministry of Education and Science
CERN
Chinese Academy of Sciences
Ministry of Science and Technology, China
National Natural Science Foundation of China
COLCIENCIAS (Colombia)
Croatian Ministry of Science, Education and Sport
Research Promotion Foundation, Cyprus
Estonian Academy of Sciences
NICPB (Estonia)
Academy of Finland
Finnish Ministry of Education
Helsinki Institute of Physics
Institut National de Physique Nucléaire et de Physique des Particules/CNRS
Commissariat à l'Énergie Atomique, France
Bundesministerium für Bildung und Forschung (Germany)
Deutsche Forschungsgemeinschaft (Germany)
Helmholtz- Gemeinschaft Deutscher For-schungszentren, Germany
General Secretariat for Research and Technology, Greece
National Scientific Research Foundation, Hungary
National Office for Research and Technology, Hungary
Department of Atomic Energy, India
Department of Science and Technology, India
Institute for Studies in Theoretical Physics and Mathematics, Iran
Science Foundation, Ireland
Istituto Nazionale di Fisica Nucleare, Italy
Korean Ministry of Education, Science and Technology
World Class University program of NRF, Korea
Lithuanian Academy of Sciences
CINVESTAV (Mexico)
SEP (Mexico)
UASLP-FAI (Mexico)
Pakistan Atomic Energy Commission
State Commission for Scientific Research, Poland
Fundação para a Ciência e a Tecnologia, Portugal
JINR (Armenia, Belarus, Georgia, Ukraine, Uzbekistan)
Ministry of Science and Technologies of the Russian Federation
Russian Ministry of Atomic Energy
Ministry of Science and Technological Development of Serbia
Ministerio de Ciencia e Innovación
Programa Consolider-Ingenio 2010, Spain
Swiss Funding Agencies (ETH Board, ETH Zurich, PSI, SNF, UniZH, Canton Zurich, and SER)
National Science Council, Taipei
Scientific and Technical Research Council of Turkey
Turkish Atomic Energy Authority
Science and Technology Facilities Council, UK
Department of Energy (DOE)
NSF
Marie-Curie IEF program (European Union)
Leventis Foundation
A. P. Sloan Foundation
Alexander von Humboldt Foundation
Associazione per lo Sviluppo Scientifico e Tecnologico del Piemonte (Italy)
Belgian Federal Science Policy Office
Fonds pour la Formation à la Recherche dans l'índustrie et dans l'Ágriculture (FRIA-Belgium)
Agentschap voor Innovatie doorWetenschap en Technologie (IWT-Belgium)

Dates

Created
2011-02-04
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Updated
2021-11-09
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