The European Physical Journal C

, Volume 49, Issue 4, pp 1099–1116 | Cite as

Electron reconstruction in CMS

  • S. Baffioni
  • C. Charlot
  • F. Ferri
  • D. Futyan
  • P. Meridiani
  • I. Puljak
  • C. Rovelli
  • R. Salerno
  • Y. Sirois
Special Article - Scientific Note

Abstract

The reconstruction of the energy and momentum of isolated electrons in CMS combining tracking and electromagnetic calorimetry information is described. The emphasis is put on primary electrons with transverse momentum below 50 GeV/c. The energy deposited in the electromagnetic calorimeter is measured in clusters of clusters (superclusters) which collect bremsstrahlung photons emitted along the electron trajectory in the tracker volume. The electron tracks are built from seeds in the pixel detector found via a cluster-driven pixel hit matching algorithm, followed by a reconstruction of trajectories in the silicon strip tracker with a Gaussian sum filter. Electrons are classified using observables sensitive to the pattern of bremsstrahlung emission and electromagnetic showering in the tracker material. Energy scale corrections depending on the electron class are applied to the supercluster and estimates of associated errors are obtained. The electron energy is deduced from a weighted combination of the corrected supercluster energy and tracker momentum measurements. The electron direction is that of the reconstructed electron track at interaction vertex. The pre-selection of isolated electron candidates for physics analysis is described. Class-dependent observables combining tracking and calorimetry information are discussed for electron identification.

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References

  1. 1.
    R. Frühwirth, Comput. Phys. Commun. 100, 1 (1997)MATHCrossRefADSGoogle Scholar
  2. 2.
    W. Adam, R. Frühwirth, A. Strandlie, T. Todorov, Reconstruction of Electrons with the Gaussian-Sum Filter in the CMS Tracker at the LHC, CMS Note 2005/001 (January 2005) pp. 11Google Scholar
  3. 3.
    ORCA, Object-oriented Reconstruction for CMS Analysis, version 8.7.3. (February 2005)Google Scholar
  4. 4.
    CMS Collaboration, The Compact Muon Solenoid – Technical Proposal, CERN/LHCC 94-38 (December 1994) pp. 290Google Scholar
  5. 5.
    CMS Collaboration, The Tracker Project – Technical Design Report, CERN/LHCC 98-6 (April 1998) pp. 625; CMS Collaboration, Addendum to the Tracker TDR, CERN/LHCC 2000-016 (February 2000) pp. 82Google Scholar
  6. 6.
    CMS Collaboration, The Electromagnetic Calorimeter Project – Technical Design Report, CERN/LHCC 97-23 (15 December 1998) pp. 364Google Scholar
  7. 7.
    S. Cucciarelli, M. Konecki, D. Kotlinski, T. Todorov, Track Reconstruction, Primary Vertex Finding and Seed Generation with the Pixel Detector, CMS NOTE-2006/026 (January 2006) pp. 22Google Scholar
  8. 8.
    D. Abbaneo, Layout and Performance of the CMS Silicon Strip Tracker, Talk given at the 9th Pisa meeting on Advanced Detector, La Biodola, Isola d’Elba, Italy (May 25–31) 2003Google Scholar
  9. 9.
    CMS Collaboration, CMS Physics Technical Design Report Vol. 1, CERN/LHCC 2006-001 (February 2006) pp. 547Google Scholar
  10. 10.
    CMS Collaboration, The Trigger and Data Acquisition Project, Vol. 1, CERN/LHCC 2000-038 (December 2000) pp. 599Google Scholar
  11. 11.
    E. Meschi, T. Monteiro, C. Seez, P. Vikas, Electron Reconstruction in the CMS Electromagnetic Calorimeter, CMS Note 2001/034 (June 2001) pp. 16Google Scholar
  12. 12.
    F. Ferri, The CMS Electromagnetic Calorimeter for the Higgs Boson Search H→ZZ(*)→4e± at the LHC, Doctor degree thesis, University of Milano-Bicocca (Italy) and Ecole Polytechnique (France) (December 2005) pp. 170Google Scholar
  13. 13.
    P. Meridiani, R. Paramatti, Use of Z→e+e- events for ECAL calibration, CMS NOTE-2006/039 (January 2006) pp. 18Google Scholar
  14. 14.
    S. Baffioni et al., J. Phys. G: Nucl. Part. Phys. 34, N23 (2007)CrossRefGoogle Scholar
  15. 15.
    P. Meridiani, Optimization of the discovery potential of the Higgs Boson in the decay channel H→ZZ(*)→4e± with the CMS detector, Doctor degree thesis, University of Roma-1 (September 2004) pp. 199Google Scholar

Copyright information

© Springer-Verlag Berlin Heidelberg 2007

Authors and Affiliations

  • S. Baffioni
    • 1
  • C. Charlot
    • 1
  • F. Ferri
    • 1
    • 2
  • D. Futyan
    • 3
  • P. Meridiani
    • 4
  • I. Puljak
    • 5
  • C. Rovelli
    • 1
    • 2
  • R. Salerno
    • 1
    • 2
  • Y. Sirois
    • 1
  1. 1.Laboratoire Leprince-RinguetEcole Polytechnique and IN2P3-CNRSPalaiseau CedexFrance
  2. 2.Università degli Studi Milano-Bicocca and INFN-Sezione di MilanoMilanoItaly
  3. 3.University of CaliforniaRiversideUSA
  4. 4.Dipartimento di Fisica and INFN-Sezione di RomaUniversità “La Sapienza”RomaItaly
  5. 5.FESBTechnical University of SplitSplitCroatia

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