https://doi.org/10.1140/epjp/i2016-16168-5
Regular Article
Particle identification in ALICE: a Bayesian approach
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A.I. Alikhanyan National Science Laboratory (Yerevan Physics Institute) Foundation, Yerevan, Armenia
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Benemérita Universidad Autónoma de Puebla, Puebla, Mexico
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Bogolyubov Institute for Theoretical Physics, Kiev, Ukraine
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Bose Institute, Department of Physics and Centre for Astroparticle Physics and Space Science (CAPSS), Kolkata, India
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Budker Institute for Nuclear Physics, Novosibirsk, Russia
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California Polytechnic State University, San Luis Obispo, California, USA
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Central China Normal University, Wuhan, China
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Centre de Calcul de l’IN2P3, Villeurbanne, France
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Centro de Aplicaciones Tecnológicas y Desarrollo Nuclear (CEADEN), Havana, Cuba
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Centro de Investigaciones Energéticas Medioambientales y Tecnológicas (CIEMAT), Madrid, Spain
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Centro de Investigación y de Estudios Avanzados (CINVESTAV), Mexico City and Mérida, Mexico
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Centro Fermi - Museo Storico della Fisica e Centro Studi e Ricerche “Enrico Fermi”, Rome, Italy
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Chicago State University, Chicago, Illinois, USA
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China Institute of Atomic Energy, Beijing, China
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Commissariat à l’Energie Atomique, IRFU, Saclay, France
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COMSATS Institute of Information Technology (CIIT), Islamabad, Pakistan
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Departamento de Física de Partıculas and IGFAE, Universidad de Santiago de Compostela, Santiago de Compostela, Spain
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Department of Physics and Technology, University of Bergen, Bergen, Norway
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Department of Physics, Aligarh Muslim University, Aligarh, India
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Department of Physics, Ohio State University, Columbus, Ohio, USA
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Department of Physics, Sejong University, Seoul, South Korea
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Department of Physics, University of Oslo, Oslo, Norway
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Dipartimento di Fisica, dell’Università ‘La Sapienza’ and Sezione INFN, Rome, Italy
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Dipartimento di Fisica, dell’Università and Sezione INFN, Cagliari, Italy
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Dipartimento di Fisica, dell’Università and Sezione INFN, Trieste, Italy
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Dipartimento di Fisica, dell’Università and Sezione INFN, Turin, Italy
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Dipartimento di Fisica e Astronomia, dell’Università and Sezione INFN, Bologna, Italy
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Dipartimento di Fisica e Astronomia, dell’Università and Sezione INFN, Catania, Italy
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Dipartimento di Fisica e Astronomia, dell’Università and Sezione INFN, Padova, Italy
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Dipartimento di Fisica “E.R. Caianiello”, dell’Università and Gruppo Collegato INFN, Salerno, Italy
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Dipartimento di Scienze e Innovazione Tecnologica, dell’Università del Piemonte Orientale and Gruppo Collegato INFN, Alessandria, Italy
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Dipartimento Interateneo di Fisica “M. Merlin”, Sezione INFN, Bari, Italy
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Division of Experimental High Energy Physics, University of Lund, Lund, Sweden
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Eberhard Karls Universität Tübingen, Tübingen, Germany
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European Organization for Nuclear Research (CERN), Geneva, Switzerland
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Excellence Cluster Universe, Technische Universität München, Munich, Germany
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Faculty of Engineering, Bergen University College, Bergen, Norway
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Faculty of Mathematics, Physics and Informatics, Comenius University, Bratislava, Slovakia
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Faculty of Nuclear Sciences and Physical Engineering, Czech Technical University in Prague, Prague, Czech Republic
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Faculty of Science, P.J. Šafárik University, Košice, Slovakia
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Faculty of Technology, Buskerud and Vestfold University College, Vestfold, Norway
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Frankfurt Institute for Advanced Studies, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Gangneung-Wonju National University, Gangneung, South Korea
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Gauhati University, Department of Physics, Guwahati, India
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Helsinki Institute of Physics (HIP), Helsinki, Finland
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Hiroshima University, Hiroshima, Japan
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Indian Institute of Technology Bombay (IIT), Mumbai, India
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Indian Institute of Technology Indore, Indore (IITI), India
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Indonesian Institute of Sciences, Jakarta, Indonesia
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Inha University, Incheon, South Korea
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Institut de Physique Nucléaire d’Orsay (IPNO), Université Paris-Sud, CNRS-IN2P3, Orsay, France
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Institut für Informatik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Institut für Kernphysik, Johann Wolfgang Goethe-Universität Frankfurt, Frankfurt, Germany
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Institut für Kernphysik, Westfälische Wilhelms-Universität Münster, Münster, Germany
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Institut Pluridisciplinaire Hubert Curien (IPHC), Université de Strasbourg, Strasbourg, France
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Institute for Nuclear Research, Academy of Sciences, Moscow, Russia
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Institute for Subatomic Physics of Utrecht University, Utrecht, the Netherlands
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Institute for Theoretical and Experimental Physics, Moscow, Russia
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Institute of Experimental Physics, Slovak Academy of Sciences, Košice, Slovakia
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Institute of Physics, Academy of Sciences of the Czech Republic, Prague, Czech Republic
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Institute of Physics, Bhubaneswar, India
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Institute of Space Science (ISS), Bucharest, Romania
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Instituto de Ciencias Nucleares, Universidad Nacional Autónoma de México, Mexico City, Mexico
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Instituto de Física, Universidad Nacional Autónoma de México, Mexico City, Mexico
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iThemba LABS, National Research Foundation, Somerset West, South Africa
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Joint Institute for Nuclear Research (JINR), Dubna, Russia
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Konkuk University, Seoul, South Korea
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Korea Institute of Science and Technology Information, Daejeon, South Korea
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KTO Karatay University, Konya, Turkey
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Laboratoire de Physique Corpusculaire (LPC), Clermont Université, Université Blaise Pascal, CNRS-IN2P3, Clermont-Ferrand, France
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Laboratoire de Physique Subatomique et de Cosmologie, Université Grenoble-Alpes, CNRS-IN2P3, Grenoble, France
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Laboratori Nazionali di Frascati, INFN, Frascati, Italy
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Laboratori Nazionali di Legnaro, INFN, Legnaro, Italy
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Lawrence Berkeley National Laboratory, Berkeley, California, USA
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Moscow Engineering Physics Institute, Moscow, Russia
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Nagasaki Institute of Applied Science, Nagasaki, Japan
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National Centre for Nuclear Studies, Warsaw, Poland
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National Institute for Physics and Nuclear Engineering, Bucharest, Romania
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National Institute of Science Education and Research, Bhubaneswar, India
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National Research Centre Kurchatov Institute, Moscow, Russia
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Niels Bohr Institute, University of Copenhagen, Copenhagen, Denmark
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Nikhef, Nationaal instituut voor subatomaire fysica, Amsterdam, Netherlands
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Nuclear Physics Group, STFC Daresbury Laboratory, Daresbury, UK
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Nuclear Physics Institute, Academy of Sciences of the Czech Republic, Řež u Prahy, Czech Republic
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Oak Ridge National Laboratory, Oak Ridge, Tennessee, USA
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Petersburg Nuclear Physics Institute, Gatchina, Russia
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Physics Department, Creighton University, Omaha, Nebraska, USA
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Physics Department, Panjab University, Chandigarh, India
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Physics Department, University of Athens, Athens, Greece
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Physics Department, University of Cape Town, Cape Town, South Africa
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Physics Department, University of Jammu, Jammu, India
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Physics Department, University of Rajasthan, Jaipur, India
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Physik Department, Technische Universität München, Munich, Germany
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Physikalisches Institut, Ruprecht-Karls-Universität Heidelberg, Heidelberg, Germany
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Purdue University, West Lafayette, Indiana, USA
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Pusan National University, Pusan, South Korea
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Research Division and ExtreMe Matter Institute EMMI, GSI Helmholtzzentrum für Schwerionenforschung, Darmstadt, Germany
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Rudjer Bošković Institute, Zagreb, Croatia
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Russian Federal Nuclear Center (VNIIEF), Sarov, Russia
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Saha Institute of Nuclear Physics, Kolkata, India
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School of Physics and Astronomy, University of Birmingham, Birmingham, UK
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Sección Física, Departamento de Ciencias, Pontificia Universidad Católica del Perú, Lima, Peru
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Sezione INFN, Bari, Italy
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Sezione INFN, Bologna, Italy
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Sezione INFN, Cagliari, Italy
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Sezione INFN, Catania, Italy
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Sezione INFN, Padova, Italy
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Sezione INFN, Rome, Italy
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Sezione INFN, Trieste, Italy
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Sezione INFN, Turin, Italy
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SSC IHEP of NRC Kurchatov institute, Protvino, Russia
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Stefan Meyer Institut für Subatomare Physik (SMI), Vienna, Austria
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SUBATECH, Ecole des Mines de Nantes, Université de Nantes, CNRS-IN2P3, Nantes, France
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Suranaree University of Technology, Nakhon Ratchasima, Thailand
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Technical University of Košice, Košice, Slovakia
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Technical University of Split FESB, Split, Croatia
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The Henryk Niewodniczanski Institute of Nuclear Physics, Polish Academy of Sciences, Cracow, Poland
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The University of Texas at Austin, Physics Department, Austin, Texas, USA
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Universidad Autónoma de Sinaloa, Culiacán, Mexico
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Universidade de São Paulo (USP), São Paulo, Brazil
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Universidade Estadual de Campinas (UNICAMP), Campinas, Brazil
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University of Houston, Houston, Texas, USA
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University of Jyväskylä, Jyväskylä, Finland
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University of Liverpool, Liverpool, UK
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University of Tennessee, Knoxville, Tennessee, USA
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University of the Witwatersrand, Johannesburg, South Africa
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University of Tokyo, Tokyo, Japan
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University of Tsukuba, Tsukuba, Japan
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University of Zagreb, Zagreb, Croatia
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Université de Lyon, Université Lyon 1, CNRS/IN2P3, Villeurbanne, France
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V. Fock Institute for Physics, St. Petersburg State University, St. Petersburg, Russia
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Variable Energy Cyclotron Centre, Kolkata, India
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Warsaw University of Technology, Warsaw, Poland
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Wayne State University, Detroit, Michigan, USA
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Wigner Research Centre for Physics, Hungarian Academy of Sciences, Budapest, Hungary
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Yale University, New Haven, Connecticut, USA
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Yonsei University, Seoul, South Korea
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Zentrum für Technologietransfer und Telekommunikation (ZTT), Fachhochschule Worms, Worms, Germany
Received:
8
February
2016
Revised:
27
March
2016
Accepted:
15
April
2016
Published online:
25
May
2016
We present a Bayesian approach to particle identification (PID) within the ALICE experiment. The aim is to more effectively combine the particle identification capabilities of its various detectors. After a brief explanation of the adopted methodology and formalism, the performance of the Bayesian PID approach for charged pions, kaons and protons in the central barrel of ALICE is studied. PID is performed via measurements of specific energy loss ( 
) and time of flight. PID efficiencies and misidentification probabilities are extracted and compared with Monte Carlo simulations using high-purity samples of identified particles in the decay channels 
, 
, and 
in p-Pb collisions at 
TeV. In order to thoroughly assess the validity of the Bayesian approach, this methodology was used to obtain corrected 
spectra of pions, kaons, protons, and 
mesons in pp collisions at 
TeV. In all cases, the results using Bayesian PID were found to be consistent with previous measurements performed by ALICE using a standard PID approach. For the measurement of 
, it was found that a Bayesian PID approach gave a higher signal-to-background ratio and a similar or larger statistical significance when compared with standard PID selections, despite a reduced identification efficiency. Finally, we present an exploratory study of the measurement of 
in pp collisions at TeV, using the Bayesian approach for the identification of its decay products.
© CERN for the benefit of the ALICE Collaboration, 2016
