Measurement of the electron reconstruction efficiency at LHCb

Research output: Contribution to journalArticlepeer-review


  • LHCb Collaboration

Colleges, School and Institutes

External organisations

  • Nikhef National Institute for Subatomic Physics
  • University of Zurich
  • University of Liverpool
  • Universidad de Santiago de Compostela
  • University of Bristol
  • Université Clermont Auvergne
  • University of Michigan
  • Istituto Nazionale di Fisica Nucleare, Sezione di Milano
  • University of Cincinnati
  • Laboratori Nazionali dell'Infn di Frascati
  • TU Dortmund University, Germany
  • CERN
  • University of Glasgow
  • Universitat Autonoma de Barcelona
  • Petersburg Nuclear Physics Institute (PNPI)
  • Imperial College London
  • Universidade Federal Do Rio de Janeiro
  • IN2P3
  • Sezione INFN di Firenze
  • Ecole Polytechnique Federale de Lausanne
  • Sezione INFN di Ferrara
  • Ruprecht-Karls-Universität Heidelberg
  • Institute for High Energy Physics (IHEP)
  • Syracuse University
  • Yandex School of Data Analysis
  • INFN Sezione di Cagliari
  • University of Warwick
  • Institute of Physics


The single electron track-reconstruction efficiency is calibrated using a sample corresponding to 1.3 fb-1 of pp collision data recorded with the LHCb detector in 2017. This measurement exploits B+ J/ψ(e+e-)K+ decays, where one of the electrons is fully reconstructed and paired with the kaon, while the other electron is reconstructed using only the information of the vertex detector. Despite this partial reconstruction, kinematic and geometric constraints allow the B meson mass to be reconstructed and the signal to be well separated from backgrounds. This in turn allows the electron reconstruction efficiency to be measured by matching the partial track segment found in the vertex detector to tracks found by LHCb's regular reconstruction algorithms. The agreement between data and simulation is evaluated, and corrections are derived for simulated electrons in bins of kinematics. These correction factors allow LHCb to measure branching fractions involving single electrons with a systematic uncertainty below 1%.


Original languageEnglish
Article numberP11023
JournalJournal of Instrumentation
Issue number11
Publication statusPublished - 22 Nov 2019


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

ASJC Scopus subject areas