A search for flavor-changing neutral currents in top-quark decays t→Zq is performed in events produced from the decay chain tt̄→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 19.7fb-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. © 2014 CERN, for the CMS Collaboration.

Chatrchyan, S., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Bergauer, T., et al. (2014). Search for flavor-changing neutral currents in top-quark decays t →zq in pp collisions at s =8TeV. PHYSICAL REVIEW LETTERS, 112(17), 171802 [10.1103/PhysRevLett.112.171802].

Search for flavor-changing neutral currents in top-quark decays t →zq in pp collisions at s =8TeV

BENAGLIA, ANDREA DAVIDE;DINARDO, MAURO EMANUELE;FIORENDI, SARA;GHEZZI, ALESSIO;GOVONI, PIETRO;LUCCHINI, MARCO TOLIMAN;MANZONI, RICCARDO ANDREA;MARTELLI, ARABELLA;MORONI, LUIGI;PAGANONI, MARCO;RAGAZZI, STEFANO;TABARELLI DE FATIS, TOMMASO;Branca, A.;De Guio, F.;
2014

Abstract

A search for flavor-changing neutral currents in top-quark decays t→Zq is performed in events produced from the decay chain tt̄→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 19.7fb-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. © 2014 CERN, for the CMS Collaboration.
Articolo in rivista - Articolo scientifico
Nuclear Physics; Thermodynamics; Models, Theoretical; Neutrons; Physics and Astronomy (all)
English
2014
112
17
171802
171802
none
Chatrchyan, S., Khachatryan, V., Sirunyan, A., Tumasyan, A., Adam, W., Bergauer, T., et al. (2014). Search for flavor-changing neutral currents in top-quark decays t →zq in pp collisions at s =8TeV. PHYSICAL REVIEW LETTERS, 112(17), 171802 [10.1103/PhysRevLett.112.171802].
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/10281/154407
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