Search for Flavor-Changing Neutral Currents in Top-Quark Decays t -> Zq in pp Collisions at root s=8 TeV


Chatrchyan S., Khachatryan V., Sirunyan A. M. , Tumasyan A., Adam W., Bergauer T., ...Daha Fazla

PHYSICAL REVIEW LETTERS, cilt.112, sa.17, 2014 (SCI İndekslerine Giren Dergi) identifier identifier identifier

  • Yayın Türü: Makale / Tam Makale
  • Cilt numarası: 112 Konu: 17
  • Basım Tarihi: 2014
  • Doi Numarası: 10.1103/physrevlett.112.171802
  • Dergi Adı: PHYSICAL REVIEW LETTERS

Özet

A search for flavor-changing neutral currents in top-quark decays t -> Zq is performed in events produced from the decay chain (tt) over bar -> Zq + Wb, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A data set collected with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 19.7 fb(-1) of proton-proton collisions at a center-of-mass energy of 8 TeV. No excess is seen in the observed number of events relative to the standard model prediction; thus, no evidence for flavor-changing neutral currents in top-quark decays is found. A combination with a previous search at 7 TeV excludes a t. Zq branching fraction greater than 0.05% at the 95% confidence level.