Citations per year
Abstract: (arXiv)
We have used the Collider Detector at Fermilab (CDF II) to search for the flavor-changing neutral-current (FCNC) top quark decay {t\goes Zc} using a technique employing ratios of and production, measured in \ppbar data corresponding to an integrated luminosity of 1.52 . The analysis uses a comparison of two decay chains, {p\bar{p}\goes t\bar{t}\goes WbWb\goes\ell\nu bjjb} and {p\bar{p}\goes t\bar{t}\goes ZcWb\goes\ell\ell cjjb}, to cancel systematic uncertainties in acceptance, efficiency, and luminosity. We validate the modeling of acceptance and efficiency for lepton identification over the multi-year dataset using another ratio of and production, in this case the observed ratio of inclusive production of to bosons. To improve the discrimination against standard model backgrounds to top quark decays, we calculate the top quark mass for each event with two leptons and four jets assuming it is a event with one of the top quarks decaying to . For additional background discrimination we require at least one jet to be identified as originating from a -quark. No significant signal is found and we set an upper limit on the FCNC branching ratio Br({t\goes Zc}) using a likelihood constructed from the top quark mass distribution and the number of events. Limits are set as a function of the helicity of the boson produced in the FCNC decay. For 100% longitudinally polarized bosons we find limits of 8.3% and 9.3% (95% C.L.) depending on the assumptions regarding the theoretical top quark pair production cross-section.- 13.85.Rm
- 14.65.Ha
- 12.60.Cn
- 13.85.Qk
- OSG : CDF
- anti-p p: interaction
- neutral current: flavor changing
- top: decay
- top: mass
- jet: multiple production
References(49)
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