Flavor changing neutral currents in ttbar decays at DØ

Abstract

We present a search for flavor changing neutral currents (FCNC) in decays of top quarks. The analysis is based on a search for $t\bar{t}\to {\ell }^{\prime }\nu \ell \bar{\ell }$+jets ($\ell ,{\ell }^{\prime }=e,\mu$) final states using 4.1 {\rm fb}${}^{-1}$ of integrated luminosity of $p\bar{p}$ collisions at $\sqrt{s}=1.96$ {\rm TeV}. We extract limits on the branching ratio $B(t\to Zq)$ ($q=u,c$ quarks), assuming anomalous $tuZ$ or $tcZ$ couplings. We do not observe any sign of such anomalous coupling and set a limit of $B<3.2$ at 95% C.L.

8 pages, 5 figures. Proceedings of the DPF-2011 Conference, Providence, RI, August 8-13, 2011