CMS logoCMS event Hgg
Compact Muon Solenoid
LHC, CERN

CMS-TOP-12-037 ; CERN-PH-EP-2013-208
Search for flavor-changing neutral currents in top-quark decays $ \mathrm{ t \to Zq } $ in pp collisions at $\sqrt{s}$ = 8 TeV
Phys. Rev. Lett. 112 (2014) 171802
Abstract: A search for flavor-changing neutral currents in top-quark decays $ \mathrm{ t \to Zq } $ is performed in events produced from the decay chain $ \mathrm{ t\bar{t} \to Zq+Wb } $, where both vector bosons decay leptonically, producing a final state with three leptons (electrons or muons). A dataset collected with the CMS detector at the LHC is used, corresponding to an integrated luminosity of 19.7 inverse femtobarns 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 $ \mathrm{ t \to Zq } $ branching fraction greater than 0.05% at the 95% confidence level.
Figures CMS Publications
Figures

png pdf
Figure 1-a:

png pdf
Figure 1-b:

png pdf
Figure 1-c:

png pdf
Figure 2-a:

png pdf
Figure 2-b:

png pdf
Figure 2-c:
Compact Muon Solenoid
LHC, CERN