A search for flavour changing neutral currents in top-quark decays in $pp$ collision data collected with the ATLAS detector at $\sqrt{s}$ = 7 TeV

Unknown, Article, Preprint English OPEN
The ATLAS Collaboration (2012)
  • Publisher: Springer
  • Journal: volume 2,012, issue 1029-8479 (issn: 1029-8479, eissn: 1029-8479)
  • Related identifiers: doi: 10.1007/JHEP09(2012)139
  • Subject: Partícules (Física nuclear) | Particle Physics - Experiment | info:eu-repo/classification/arxiv/High Energy Physics::Phenomenology | Hadron Hadron Scattering; Top Physics; Rare Decays; Flavour Changing Neutral Currents | Flavour changing neutral currents | Hadron-hadron scattering | 530 | QC | Rare decays | info:eu-repo/classification/ddc/ddc:530 | Física | High Energy Physics - Experiment | info:eu-repo/classification/arxiv/High Energy Physics::Experiment | Detectors de radiació | Física nuclear | Top physics | Nuclear and High Energy Physics | Col·lisions (Física nuclear)
    • ddc: ddc:539 | ddc:530
    arxiv: High Energy Physics::Phenomenology | High Energy Physics::Experiment

A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of $\sqrt{s}$ = 7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb$^{-1}$, were used. A search was performed for top-quark pair-production events, with one top quark decaying through the $t \to Zq$ FCNC (q=u,c) channel, and the other through the Standard Model dominant mode $t \to Wb$. Only the decays of the Z boson to charged leptons and leptonic W-boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the $t \to Zq$ branching ratio of BR$(t \to Zq)<0.73$% is set at the 95% confidence level. A search for flavour changing neutral current (FCNC) processes in top-quark decays by the ATLAS Collaboration is presented. Data collected from pp collisions at the LHC at a centre-of-mass energy of sqrt(s) = 7 TeV during 2011, corresponding to an integrated luminosity of 2.1 fb^-1, were used. A search was performed for top-quark pair-production events, with one top quark decaying through the t->Zq FCNC (q=u,c) channel, and the other through the Standard Model dominant mode t->Wb. Only the decays of the Z boson to charged leptons and leptonic W-boson decays were considered as signal. Consequently, the final-state topology is characterised by the presence of three isolated charged leptons, at least two jets and missing transverse momentum from the undetected neutrino. No evidence for an FCNC signal was found. An upper limit on the t->Zq branching ratio of BR(t->Zq)<0.73% is set at the 95% confidence level.
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