Search for anomalous single top quark production in association with a photon in pp collisions at √s = 8 TeV


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Khachatryan V., Sirunyan A., Tumasyan A., Adam W., Asilar E., Bergauer T., ...More

Journal of High Energy Physics, vol.2016, no.4, 2016 (SCI-Expanded, Scopus) identifier identifier identifier

  • Publication Type: Article / Article
  • Volume: 2016 Issue: 4
  • Publication Date: 2016
  • Doi Number: 10.1007/jhep04(2016)035
  • Journal Name: Journal of High Energy Physics
  • Journal Indexes: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Keywords: Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Top physics
  • Open Archive Collection: AVESIS Open Access Collection
  • Yıldız Technical University Affiliated: Yes

Abstract

The result of a search for flavor changing neutral currents (FCNC) through single top quark production in association with a photon is presented. The study is based on proton-proton collisions at a center-of-mass energy of 8 TeV using data collected with the CMS detector at the LHC, corresponding to an integrated luminosity of 19.8 fb−1. The search for tγ events where t → Wb and W → μν is conducted in final states with a muon, a photon, at least one hadronic jet with at most one being consistent with originating from a bottom quark, and missing transverse momentum. No evidence of single top quark production in association with a photon through a FCNC is observed. Upper limits at the 95% confidence level are set on the tuγ and tcγ anomalous couplings and translated into upper limits on the branching fraction of the FCNC top quark decays: ℬ(t → uγ) < 1.3 × 10− 4 and ℬ(t → cγ) < 1.7 × 10− 3. Upper limits are also set on the cross section of associated tγ production in a restricted phase-space region. These are the most stringent limits currently available.