Measurement of the W boson helicity in events with a single reconstructed top quark in pp collisions at √s = 8 TeV


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The CMS collaboration C., Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Bergauer T., ...More

Journal of High Energy Physics, vol.2015, no.1, 2015 (SCI-Expanded) identifier

  • Publication Type: Article / Article
  • Volume: 2015 Issue: 1
  • Publication Date: 2015
  • Doi Number: 10.1007/jhep01(2015)053
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Electroweak interaction, Hadron-Hadron Scattering
  • Erzincan Binali Yildirim University Affiliated: Yes

Abstract

© 2015, The Author(s).A measurement of the W boson helicity is presented, where the W boson originates from the decay of a top quark produced in pp collisions. The event selection, optimized for reconstructing a single top quark in the final state, requires exactly one isolated lepton (muon or electron) and exactly two jets, one of which is likely to originate from the hadronization of a bottom quark. The analysis is performed using data recorded at a center-of-mass energy of 8 TeV with the CMS detector at the CERN LHC in 2012. The data sample corresponds to an integrated luminosity of 19.7 fb−1. The measured helicity fractions are FL = 0.298 ± 0.028 (stat) ± 0.032(syst), F0 = 0.720 ± 0.039 (stat) ± 0.037(syst), and FR = −0.018 ± 0.019 (stat) ± 0.011(syst). These results are used to set limits on the real part of the tWb anomalous couplings, gL and gR.