Search for anomalous Wtb couplings and flavour-changing neutral currents in t-channel single top quark production in pp collisions at √s=7 and 8 TeV


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

Journal of High Energy Physics, cilt.2017, sa.2, 2017 (SCI-Expanded) identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 2017 Sayı: 2
  • Basım Tarihi: 2017
  • Doi Numarası: 10.1007/jhep02(2017)028
  • Dergi Adı: Journal of High Energy Physics
  • Derginin Tarandığı İndeksler: Science Citation Index Expanded (SCI-EXPANDED), Scopus
  • Anahtar Kelimeler: Flavour Changing Neutral Currents, Hadron-Hadron scattering (experiments), Top physics
  • Erzincan Binali Yıldırım Üniversitesi Adresli: Evet

Özet

© 2017, The Author(s).Single top quark events produced in the t channel are used to set limits on anomalous Wtb couplings and to search for top quark flavour-changing neutral current (FCNC) interactions. The data taken with the CMS detector at the LHC in proton-proton collisions at s=7 and 8 TeV correspond to integrated luminosities of 5.0 and 19.7 fb−1, respectively. The analysis is performed using events with one muon and two or three jets. A Bayesian neural network technique is used to discriminate between the signal and backgrounds, which are observed to be consistent with the standard model prediction. The 95% confidence level (CL) exclusion limits on anomalous right-handed vector, and left- and right-handed tensor Wtb couplings are measured to be |fV R| < 0.16, |fT L| < 0.057, and − 0.049 < fT R < 0.048, respectively. For the FCNC couplings κtug and κtcg, the 95% CL upper limits on coupling strengths are |κtug|/Λ < 4.1 × 10− 3 TeV−1 and |κtcg|/Λ < 1.8 × 10− 2 TeV−1, where Λ is the scale for new physics, and correspond to upper limits on the branching fractions of 2.0 × 10−5 and 4.1 × 10−4 for the decays t → ug and t → cg, respectively.[Figure not available: see fulltext.]