Testing flavor - changing neutral currents in the rare top quark decays t → cV

Testing flavor - changing neutral currents in the rare top quark decays

Search for flavor changing neutral currents in decays of top quarks

We present a search for flavor changing neutral currents in decays of top quarks. The analysis is based on a search for t ¯ t → ℓ ′ νℓ ¯ ℓ+jets (ℓ, ℓ ′ = e, µ) final states using 4.1 fb −1 of integrated luminosity of p¯ p collisions at √ s = 1.96 TeV. We extract limits on the branching ratio B(t → Zq) (q = u, c quarks), assuming anomalous tuZ or tcZ couplings. We do not observe any sign of such...

Loop Induced Flavor Changing Neutral Decays of the Top Quark in a General Two-Higgs-Doublet Model

Decays of the top quark induced by flavor changing neutral currents (FCNC) are known to be extremely rare events within the Standard Model. This is so not only for the decay modes into gauge bosons, but most notably in the case of the Higgs channels, e.g. t → HSM + c, with a branching fraction of 10 at most. Therefore, detection of FCNC top quark decays in a future high-energy, and high-luminos...

Top-Quark Decay Via Flavor-Changing Neutral Currents at Hadron Colliders

We study low energy experimental constraints on an anomalous top-quark coupling associated with the flavor-changing neutral current vertex Zt̄c. In view of these constraints, we discuss the experimental observability of the induced rare decay mode t → Zc, both at the Fermilab Tevatron (with the Main Injector or a luminosity-upgrade) and at the LHC.

Flavor-changing top quark decays in R-parity-violating supersymmetric models

The flavor changing top quark decays t → cV (V = Z, γ, g) induced by R-parity-violating couplings in the minimal supersymmetric standard model (MSSM) are evaluated. We find that the decays t → cV can be significantly enhanced relative to those in the R-parity conserving SUSY model. Our results show that the top quark FCNC decay can be as large as Br(t → cg) ∼ 10−3, Br(t → cZ) ∼ 10−4 and Br(t → ...