Search for flavor-changing neutral currents in top-quark decays t → Zq in pp collisions at sqrt[s] = 8 TeV.

Journal article

A search for flavor-changing neutral currents in top-quark decays t → Zq is performed in events produced from the decay chain tt → 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.

Authors: Chatrchyan, S; Khachatryan, V; Sirunyan, A; Tumasyan, A; Adam, W

• Publication status: Published
• Journal: Physical Review Letters
• Volume: 112
• Issue: 17
• Pages: 171802
• Publication date: 2014-05-02
• DOI: 10.1103/PhysRevLett.112.171802
• EISSN: 1079-7114
• ISSN: 0031-9007
• Language: English
• Keywords: CMS Collaboration; Neutrons; Nuclear Physics; Thermodynamics; Models, Theoretical