Description and performance of track and primary-vertex reconstruction with the CMS tracker

The CMS collaboration

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337 Citations (Scopus)


A description is provided of the software algorithms developed for the CMS tracker both for reconstructing charged-particle trajectories in proton-proton interactions and for using the resulting tracks to estimate the positions of the LHC luminous region and individual primary-interaction vertices. Despite the very hostile environment at the LHC, the performance obtained with these algorithms is found to be excellent. For t events under typical 2011 pileup conditions, the average track-reconstruction efficiency for promptly-produced charged particles with transverse momenta of pT> 0.9GeV is 94% for pseudorapidities of |η| < 0.9 and 85% for 0.9 < |η| < 2.5. The inefficiency is caused mainly by hadrons that undergo nuclear interactions in the tracker material. For isolated muons, the corresponding efficiencies are essentially 100%. For isolated muons of pT= 100GeV emitted at |η| < 1.4, the resolutions are approximately 2.8% in pT, and respectively, 10μm and 30μm in the transverse and longitudinal impact parameters. The position resolution achieved for reconstructed primary vertices that correspond to interesting pp collisions is 10-12μm in each of the three spatial dimensions. The tracking and vertexing software is fast and flexible, and easily adaptable to other functions, such as fast tracking for the trigger, or dedicated tracking for electrons that takes into account bremsstrahlung.

Original languageEnglish
Article numberP10009
JournalJournal of Instrumentation
Issue number10
Publication statusPublished - 1 Jan 2014
Externally publishedYes

Bibliographical note

Publisher Copyright:
© CERN 2014 for the benefit of the CMS collaboration.


FundersFunder number
Not addedST/H00081X/2
Agentschap voor Innovatie door Wetenschap en Technologie
Austrian Science Fund
Bundesministerium für Bildung und Forschung
Chinese Academy of Sciences
Consejo Nacional de Ciencia y Tecnología
Coordenação de Aperfeiçoamento de Pessoal de Nível Superior
Deutsche Forschungsgemeinschaft
Estonian Research CouncilIUT23-6, IUT23-4
European Research Council
Fundação para a Ciência e a Tecnologia
General Secretariat for Research and Technology
Istituto Nazionale di Fisica Nucleare
Joint Institute for Nuclear Research
Ministry of Education
Ministry of Education, Science and Technology
Ministry of Science and Technology
National Academy of Sciences
National Natural Science Foundation of China
National Research Foundation
National Science Foundation
National Science and Technology Development Agency
Physicians' Services Incorporated Foundation
Research Promotion Foundation
Russian Academy of Sciences
Russian Foundation for Basic Research
Science and Technology Facilities Council
Swiss National Science Foundation
University of Malaya
National Science Foundation1306040, 1151640, 1306953, 1314131, 0906479, 1306951, 1205960, 1120138
Science and Technology Facilities CouncilST/L00609X/1, ST/I505572/1, ST/I005912/1, ST/J005665/1, ST/J004901/1, ST/K001256/1, ST/K003844/1, ST/L006340/1, GRIDPP, ST/F007094/1
Schweizerischer Nationalfonds zur F&#x00F6;rderung der Wissenschaftlichen Forschung146730, 153664


    • Large detectorsystems performance
    • Pattern recognition, cluster finding, calibration and fitting methods
    • Performance of High Energy Physics Detectors


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